CN105803637A - Curved shallow-crossing linking structure carbon fiber/copper fiber carbon-based friction material and preparation method thereof - Google Patents

Abstract

The invention discloses a curved shallow-crossing linking structure carbon fiber/copper fiber carbon-based friction material and a preparation method thereof.The preparation method of the friction material comprises the following steps that 1, preparation of a curved shallow-crossing linking structure carbon fiber/copper fiber preform is conducted and includes (1) warp yarn preparation, (2) weft yarn preparation, (3) warping, (4) drafting and denting, (5) weaving and (6) take-up and let-off; 2, CVI deposition is performed: the carbon fiber/copper fiber perform is arranged in a CVI system for deposition to prepare the friction material.Long carbon fibers and copper fibers are mixed and woven for preparation of the friction material, the advantages of the two types of fibers are fully played and the shortcomings of the fibers are overcome to achieve the effect of overcoming their own shortcomings by learning from their strong points.

Description

A carbon fiber/copper fiber carbon-based friction material with shallow cross-bending structure and its preparation method

technical field

The invention relates to the technical field of material processing, in particular to a manufacturing process of a shallow cross-bending carbon fiber/copper fiber carbon-based friction composite material.

Background technique

Carbon fiber/copper fiber reinforced carbon-based friction materials have a simple preparation process, less cleaning and pollution, good thermal stability, mechanical properties and excellent friction and wear properties, and have broad development prospects. In recent years, there have been a large number of friction materials related to carbon fiber hybrid hot pressing, but most of them use chopped hybrid fibers. However, it has the disadvantages of poor structural integrity, low designability, and easy delamination and damage. It is difficult to withstand large torsional moments, and it is prone to failure under harsh working conditions such as high speed and high pressure. It is only used in medium and low load situations. However, in the direction of high speed and heavy load, higher requirements are put forward for the safety and stability of the braking system. How to overcome the above-mentioned defects of friction materials becomes the key to solving the problem.

The 2.5-dimensional woven structure is the three-dimensional angular interlocking structure, including three-dimensional orthogonal, shallow cross-bending and deep cross-linking and other structural forms. The direction configuration at a certain angle overcomes the delamination problem and increases the inter-incremental shear strength, making the 2.5-dimensional composite material have excellent structural designability, overall impact resistance and fatigue resistance. At the same time, this process adopts the method of mixing carbon fiber and copper fiber, which not only makes up for each other's shortcomings, but also reduces the cost.

Contents of the invention

In view of the above problems in the prior art, the applicant provides a carbon fiber/copper fiber carbon-based friction material with a shallow cross-bending structure and a preparation method thereof. In the method of the present invention, the carbon fiber and the copper fiber are parallel-twisted first to make a ply yarn, and then weaving is performed, and the warp yarn is bound to pass through the entire thickness direction of the material to form a three-dimensional structure, which overcomes the problem of delamination and increases the interlayer shear strength At the same time, the co-twisting technology of copper fiber and carbon fiber is adopted, which greatly reduces the production cost and adopts the carbon deposition method, which makes the preparation method simple and easy to popularize.

Technical scheme of the present invention is as follows:

A carbon fiber/copper fiber carbon-based friction material with a shallow cross-bending structure. The preparation method of the friction material includes the following steps:

(1) Preparation of carbon fiber/copper fiber prefabricated body with shallow cross-bending structure:

① Warp yarn, using multi-strand twisted copper fibers as warp yarn;

② Weft yarn, carbon fiber and copper fiber are twisted and plyed as weft yarn;

③Warping, the creel let-off method is adopted, the warp yarn is wound on the cylindrical bobbin, and directly introduced into the sample loom from the creel;

④Dressing and reeding, adopting the forward threading method, each cycle has 8 warp yarns, and passes through the corresponding 8 palm frames in sequence;

⑤ Weaving, weave 2-10 layers of carbon fiber/copper fiber woven fabrics with shallow cross-bending structure on the three-dimensional loom sample machine. 2-10mm, the diameter density is 40 strands/10cm, the weft density is 80-200 strands/10cm, the weaving tension is moderate, and the shallow cross-bend carbon fiber/copper fiber prefabricated body is obtained; the multi-layer shallow cross-bend carbon fiber/copper fiber Copper fiber prefabricated body, the volume content of carbon fiber is 10-50%, and the volume content of copper fiber is 20-60%;

⑥ coiling and let-off, the small rapier prototype machine used is used for automatic coiling and let-off, and the woven sample cloth is cut to obtain the carbon fiber/copper fiber prefabricated body;

(2) CVI deposition:

Put the carbon fiber/copper fiber prefabricated body in the CVI system, place the prefabricated body under the air inlet, then close the furnace door, and first pass nitrogen gas to remove the air in the furnace to ensure an inert atmosphere; then heat the furnace temperature according to the heating program. It is raised to 950°C, the dilute gas nitrogen and the precursor propylene are fed, and the deposition is carried out under the same process conditions; finally, after the temperature in the furnace is lowered to room temperature, the sample is taken out and ground to obtain the friction material.

The preparation method of the warp in the step (1) is as follows: 1-10 strands of 1650dtex copper fibers are parallel-twisted, and the twist is 4-10 twists/10cm.

The weft yarn in described step (1) adopts following formula to determine the massfraction of carbon fiber and copper fiber:

In the formula, Nt-represents the linear density of the yarn, tex; Gk-represents the weight of the yarn at the specified moisture regain, g;

$\mathrm{<span\; class="notranslate">\; N</span>}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1000</span>}{\mathrm{<span\; class="notranslate">\; G</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}}{\mathrm{<span\; class="notranslate">\; L</span>}}$

L- indicates the length of the yarn, m.

Reeding in the step (1) adopts metric 40# steel reed, one reed and one reed.

The heating program in the step (2) is as follows: at room temperature, proceed at a heating rate of 17-21°C/h, heat up to 300°C, keep warm for 3 hours, and then raise the temperature at a heating rate of 25-30°C to 950°C.

In the step (2), the flow rates of the diluent gas nitrogen and the precursor propylene are 20cm ³ /s-30cm ³ /s and 10-30cm ³ /s respectively.

The deposition process in the step (2) is divided into 4 to 6 cycles, and the deposition time of each cycle is 120 hours.

The beneficial technical effects of the present invention are:

(1) For the first time, the present invention adopts the mixed weaving of long carbon fiber and copper fiber for the preparation of friction material. Give full play to the advantages of the two fibers and make up for each other's deficiencies to achieve the effect of learning from each other.

(2) The present invention first applies shallow cross-bending structure reinforcement technology to the preparation of friction materials, and the resulting carbon fiber/copper fiber reinforced carbon-based friction material has a three-dimensional structure formed by the binding warp yarns in the entire thickness direction of the material, which overcomes the problem of detachment. The layer problem increases the interlayer shear strength, has excellent structural designability, overall impact resistance and fatigue resistance, significantly enhances the bending strength and shear strength of the friction material, and significantly improves the mechanical strength of the material.

(3) The present invention introduces carbon deposition technology into the preparation of friction materials for the first time, replacing the method of hot pressing of phenolic resin, which makes the preparation process simpler, the product quality is high, and the production cost is low, which is convenient for popularization and application.

(4) The carbon fiber-reinforced friction material of the present invention has the best thermal decay resistance, but the carbon fiber is prone to brittle fracture and the price of the carbon fiber is more expensive; however, the copper fiber can overcome the thermal sensitivity of the resin, improve the stability of the friction coefficient, and reduce the wear rate , while the compressive properties of its composites are poor. An increase in the content of carbon fibers will improve the friction performance of the friction material, but the mechanical properties of the material will decrease and the cost will increase. The yarn strength will first increase and then decrease with the increase of yarn twist. As the thickness of the fabric increases, the integrity of the fabric is better, and the mechanical properties of the fabric increase, but the gaps between the fabrics decrease, which is not conducive to the entry of carbon base, and ultimately affects its friction and mechanical properties. The conditions of the present invention reach a comprehensive balance. , so that the final friction material has better performance.

detailed description

Below in conjunction with embodiment, the present invention is described in detail.

Example 1

A carbon fiber/copper fiber carbon-based friction material with a shallow cross-bending structure. The preparation method of the friction material includes the following steps:

(1) Preparation of carbon fiber/copper fiber prefabricated body with shallow cross-bending structure:

① warp yarn, 1 strand of 1650dtex copper fiber is parallel twisted, and the twist is 4 twists/10cm, as the warp yarn;

② Weft yarn, the carbon fiber and copper fiber are twisted and plied as the weft yarn; the following formula is used for the weft yarn to determine the mass fraction of carbon fiber and copper fiber:

$\mathrm{<span\; class="notranslate">\; N</span>}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1000</span>}{\mathrm{<span\; class="notranslate">\; G</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}}{\mathrm{<span\; class="notranslate">\; L</span>}}$

In the formula, Nt-represents the linear density of the yarn, tex; Gk-represents the weight of the yarn at a given moisture regain, g; L-represents the length of the yarn, m; the mixing ratio of carbon fiber and copper fiber in the weft yarn is 1: 0, that is, 3 strands of carbon fiber are parallel-twisted and plied as the weft yarn.

③Warping, the creel let-off method is adopted, the warp yarn is wound on the cylindrical bobbin, and directly introduced into the sample loom from the creel;

③Dressing and reeding adopts the method of threading, and each cycle has 8 warp yarns, which pass through the corresponding 8 palm frames in sequence;

④Weaving: Weave two layers of carbon fiber copper fiber woven fabric with shallow cross-bending structure on the three-dimensional loom prototype. The weaving density is 40 threads/10cm, the weft density is 80 threads/10cm, and the weaving tension is moderate, which is worthy of shallow cross-bend carbon fiber/copper fiber prefabrication; the carbon fiber and copper fiber are both long filaments with certain weavability. In the two-layer shallow cross-bending carbon fiber/copper fiber prefabricated body, the carbon fiber volume content is 25%, and the copper fiber volume content is 30%.

⑥ coiling and let-off, the adopted small rapier machine automatically coils and let-off, and cuts out the woven sample cloth to obtain the carbon fiber/copper fiber prefabricated body.

(2) CVI deposition:

Place the carbon fiber/copper fiber prefabricated body in the CVI system, place the prefabricated body above the air inlet, then close the furnace door, and first pass nitrogen gas to remove the air in the furnace to ensure an inert atmosphere; then the furnace temperature is at room temperature , carried out at a heating rate of 17°C/h. When the temperature was raised to 300°C, the temperature was kept for 3 hours, and then the temperature was raised to 950°C at a heating rate of 25°C. Dilute gas nitrogen and precursor propylene (20cm ³ /s, 10cm ³ /s), depositing under the same process conditions, 4 cycles, each cycle of deposition time is 120h; finally, after the furnace temperature dropped to room temperature, the samples were taken out and ground to obtain the friction material. The performance tests of the obtained materials are shown in Table 1.

Example 2

A carbon fiber/copper fiber carbon-based friction material with a shallow cross-bending structure. The preparation method of the friction material includes the following steps:

(1) Preparation of carbon fiber/copper fiber prefabricated body with shallow cross-bending structure:

① Warp yarn, 5 strands of 1650dtex copper fiber are parallel twisted, and the twist is 7 twists/10cm, as the warp yarn;

② Weft yarn, the carbon fiber and copper fiber are twisted and plied as the weft yarn; the weft yarn is determined by the following formula

$\mathrm{<span\; class="notranslate">\; N</span>}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1000</span>}{\mathrm{<span\; class="notranslate">\; G</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}}{\mathrm{<span\; class="notranslate">\; L</span>}}$

Mass fraction of carbon fiber and copper fiber:

In the formula, Nt-represents the linear density of the yarn, tex; Gk-represents the weight of the yarn at a given moisture regain, g; L-represents the length of the yarn, m; the mixing ratio of carbon fiber and copper fiber in the weft yarn is 2: 1. 2 strands of carbon fiber and 5 strands of copper fiber are twisted and plied as weft yarn.

③Warping, the creel let-off method is adopted, the warp yarn is wound on the cylindrical bobbin, and directly introduced into the sample loom from the creel;

④Dressing and reeding, adopting the forward threading method, each cycle has 8 warp yarns, and passes through the corresponding 8 palm frames in sequence;

⑤Weaving, weaving four layers of carbon fiber copper fiber woven fabric with shallow cross-bending structure on the three-dimensional loom prototype. The weaving density is 40 threads/10cm, the weft density is 160 threads/10cm, and the weaving tension is moderate, which is worthy of shallow cross-bend carbon fiber/copper fiber prefabrication; the carbon fiber and copper fiber are both long filaments with certain weavability. In the four-layer shallow cross-bending carbon fiber/copper fiber prefabricated body, the volume content of carbon fiber is 20%, and the volume content of copper fiber is 40%.

⑥ coiling and let-off, the adopted small rapier machine automatically coils and let-off, and cuts out the woven sample cloth to obtain the carbon fiber/copper fiber prefabricated body.

(2) CVI deposition:

Put the carbon fiber/copper fiber prefabricated body in the CVI system, place the prefabricated body under the air inlet, then close the furnace door, and first pass nitrogen gas to remove the air in the furnace to ensure an inert atmosphere; then keep the furnace temperature at room temperature , carried out at a heating rate of 19°C/h, heated to 300°C, kept the temperature for 3 hours, then raised the temperature to 950°C at a heating rate of 27°C, and fed dilute gas nitrogen and precursor propylene (25cm ³ /s, 20cm ³ /s), depositing under the same process conditions, 5 cycles, and the deposition time of each cycle is 120h; finally, after the temperature in the furnace is lowered to room temperature, the sample is taken out, and the friction material is obtained by grinding. The performance tests of the obtained materials are shown in Table 1.

Example 3

A carbon fiber/copper fiber carbon-based friction material with a shallow cross-bending structure. The preparation method of the friction material includes the following steps:

(1) Preparation of carbon fiber/copper fiber prefabricated body with shallow cross-bending structure:

① Warp yarn, 10 strands of 1650dtex copper fibers are parallel twisted, and the twist is 10 twists/10cm, as the warp yarn;

② Weft yarn, the carbon fiber and copper fiber are twisted and plied as the weft yarn; the following formula is used for the weft yarn to determine the mass fraction of carbon fiber and copper fiber:

$\mathrm{<span\; class="notranslate">\; N</span>}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1000</span>}{\mathrm{<span\; class="notranslate">\; G</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}}{\mathrm{<span\; class="notranslate">\; L</span>}}$

In the formula, Nt-represents the linear density of the yarn, tex; Gk-represents the weight of the yarn at a given moisture regain, g; L-represents the length of the yarn, m; the mixing ratio of carbon fiber and copper fiber in the weft yarn is 1: 2. That is, 1 strand of carbon fiber and 10 strands of copper fiber are twisted and plied as weft yarn.

③Warping, the creel let-off method is adopted, the warp yarn is wound on the cylindrical bobbin, and directly introduced into the sample loom from the creel;

④Dressing and reeding, adopting the forward threading method, each cycle has 8 warp yarns, and passes through the corresponding 8 palm frames in sequence;

⑤ Weaving, weaving six layers of carbon fiber copper fiber woven fabric with shallow cross-bending structure on the three-dimensional loom prototype, the binding warp yarn is arranged along the direction of 60° to the thickness direction, and runs through the entire thickness direction of the material, the thickness is about 8mm, and the diameter is dense. The weaving density is 40 threads/10cm, the weft density is 200 threads/10cm, and the weaving tension is moderate, which is worthy of shallow cross-bending carbon fiber/copper fiber prefabrication; the carbon fiber and copper fiber are both filaments and have certain weavability. In the six-layer shallow cross-bending carbon fiber/copper fiber prefabricated body, the carbon fiber volume content is 15%, and the copper fiber volume content is 50%.

⑥ coiling and let-off, the adopted small rapier machine automatically coils and let-off, and cuts out the woven sample cloth to obtain the carbon fiber/copper fiber prefabricated body.

(2) CVI deposition:

Put the carbon fiber/copper fiber prefabricated body in the CVI system, place the prefabricated body under the air inlet, then close the furnace door, and first pass nitrogen gas to remove the air in the furnace to ensure an inert atmosphere; then keep the furnace temperature at room temperature , carried out at a heating rate of 21°C/h. When the temperature was raised to 300°C, the temperature was kept for 3 hours, and then the temperature was raised to 950°C at a heating rate of 30°C. Dilute gas nitrogen and precursor propylene (30cm ³ /s, 30cm ³ /s), under the same process conditions, the deposition was carried out in 6 cycles, and the deposition time of each cycle was 120h; finally, after the temperature in the furnace dropped to room temperature, the samples were taken out and ground to obtain the friction material. The performance tests of the obtained materials are shown in Table 1.

Table 1

According to the data obtained through testing, the coefficient of friction is stable at about 0.3. If the friction coefficient is too high, the braking effect will increase, but the wear will rise sharply, and the temperature will increase, which is not conducive to the long-term use of the brake material; if the friction coefficient is too small, the braking will not be obvious, and the effect will not be good; service life.

Claims (7)

1. the curved structural carbon fiber of shallow friendship/copper fiber charcoal base frication material, it is characterised in that the preparation method of this friction material comprises the steps:

(1) the curved structural carbon fiber of shallow friendship/copper fiber preform is prepared:

1. warp thread, using multiply the copper fiber after twisting with the fingers as warp thread；

2. weft yarn, using carbon fiber and copper fiber twisted stock as weft yarn；

3. warping, adopts bobbin cradle warp let-off mode, is wound on cheese by warp rolls, is introduced directly into small sample loom from bobbin cradle；

4. gaiting denting, adopt along wearing method, each circulation has 8 warp thread, sequentially through 8 corresponding brown frames；

5. weave, three-dimensional loom small model machine is weaved 2～10 layers of curved structural carbon fiber of shallow friendship/copper fibre fabric, attachment warp edge and thickness direction are 0～90 ° of direction configuration, and the through whole thickness direction of material, thickness is 2～10mm about, and footpath is close is 40/10cm, and filling density is 80～200/10cm, weaving tension appropriateness, prepares the curved carbon fiber of shallow friendship/copper fiber preform；The curved carbon fiber of the shallow friendship of described multilamellar/copper fiber preform, carbon fiber volume content is 10～50%, and copper fiber volume fraction is 20～60%；

6. the warp let-off is batched, the arrow shaft small model machine automatic rolling of employing and the warp let-off, and the sample cloth cutting weaved is got off, prepare described carbon fiber/copper fiber preform；

(2) CVI deposition:

Carbon fiber/copper fiber preform is placed in CVI system, precast body is placed in above air inlet, is then shut off fire door, first pass into nitrogen to get rid of furnace air and guarantee inert atmosphere；Again furnace temperature is raised to 950 DEG C by heating schedule heating, passes into diluent gas nitrogen and presoma propylene, be deposited under identical process conditions；Finally, after in-furnace temperature is down to room temperature, takes out sample, carry out grinding and prepare described friction material.

2. friction material according to claim 1, it is characterised in that in described step (1), the preparation method of warp thread is: the 1650dtex copper fiber of 1～10 strand is carried out and twisted with the fingers, and the twist is 4～10 sth. made by twisting/10cm.

3. friction material according to claim 1, it is characterised in that in described step (1), weft yarn adopts equation below to determine the mass fraction of carbon fiber and copper fiber:

$Nt=\frac{1000G_k}{L}$

In formula, Nt-represents the line density of yarn, tex；Gk-represents the yarn weight when official regain, g；L-represents the length of yarn, m.

4. friction material according to claim 1, it is characterised in that in described step (1), denting adopts metric system 40# reed, and a reed one is worn.

5. friction material according to claim 1, it is characterized in that in described step (2), heating schedule is: when room temperature, carry out with the programming rate of 17～21 DEG C/h, under the state being warming up to 300 DEG C, insulation 3h, then it is warming up to 950 DEG C with the programming rate of 25～30 DEG C.

6. friction material according to claim 1, it is characterised in that the flow of diluent gas nitrogen and presoma propylene 20cm respectively in described step (2)³/ s～30cm³/ s, 10～30cm³/s。

7. friction material according to claim 1, it is characterised in that in described step (2), deposition process divides 4～6 cycles to carry out, and each cycle sedimentation time is 120h.