CN103769592B - A kind of preparation method of spherical TiC/Fe cermet composite particles - Google Patents

Abstract

The invention provides a method for preparing spherical TiC/Fe composite particles, which belongs to the field of cermet composite materials. Using cheap Ti/Fe powder and sucrose as raw materials, the precursor powder is obtained by mechanical ball milling, drying, carbonization, crushing and sieving, and the self-reaction synthesis is induced by inductively coupled plasma spraying, and finally spherical TiC/Fe composite particles are obtained . The prepared metal-ceramic composite particles have good sphericity, compact structure, metal phase and ceramics are evenly dispersed and distributed, and have good wettability. The method of the invention has the advantages of simple process, short process, low energy consumption, abundant and easy-to-obtain raw materials, and low cost.

Description

A kind of preparation method of spherical TiC/Fe cermet composite particle

technical field

The invention relates to the field of composite material manufacturing and belongs to the category of cermet composite materials. In particular, a method for preparing spherical TiC/Fe cermet composite particles is provided.

Background technique

Ceramic-reinforced metal-matrix composites combine the advantages of ceramics and metals. They not only have the high hardness, high strength, and high melting point of ceramic materials, but also have good machinability and high electrical and thermal conductivity of metals. Their applications have been extremely popular in recent years. big development.

TiC ceramics are widely used in the preparation of TiC particle reinforced cermet composites because of their low friction coefficient, high hardness, low density and good high temperature stability. Among them, TiC/Fe composite material has gradually developed into a wear-resistant coating material and cutting tool material with broad industrial application prospects due to its unique high specific strength, high specific modulus, wear resistance and high temperature resistance. .

In the powder metallurgy production process, the raw material powder is one of the key factors affecting the final performance of the product. Whether it is the plasma coating raw material powder used for material protection, or the raw material powder used to prepare hard tools and ceramic/metal composite materials, it is a multi-component mixture composed of hard phases and metals or alloys. It is difficult to obtain uniform composite powder only by mechanical mixing. Moreover, the TiC ceramic phase has the problem of poor wettability with the Fe metal matrix, which is likely to cause contamination of the bonding interface and reduce the performance of the product.

Composite particles are high-quality raw materials for surface strengthening materials and high-performance composite materials that have emerged in recent years. It can be used to prepare coatings with properties such as wear resistance, corrosion resistance, heat resistance and high temperature oxidation resistance, and can also prepare multi-element metal and Metal-ceramic system composite materials. At present, the production of composite particles in my country mainly adopts the liquid-phase hydrogenation reduction method, which has complex processes, many influencing factors and limited product varieties; other existing production methods cannot meet social needs.

The emerging inductively coupled plasma technology has the advantages of high temperature, less pollution, and adjustable and controllable atmosphere. Inductively coupled plasma technology is a good way to prepare spherical powder with uniform composition, few defects and good fluidity, which has both low production cost and high productivity. In order to pre-alloy metals, homogenize and compact heterogeneous mixtures with large density differences, and obtain spheroidized powders with good mutual dispersibility of metal/ceramic two phases, spherical TiC/Fe composite particles are prepared by inductively coupled plasma technology method has not been reported yet.

Contents of the invention

The purpose of the present invention is to provide a method for preparing spherical metal-ceramic composite particles with uniform two-phase dispersion, simple process, controllable process, and low cost, so as to solve the problem of high cost, complex process, difficult control, and production cycle of existing methods. Long and other disadvantages.

The technical solution adopted in the present invention is: using low-cost Ti/Fe powder and sucrose as raw materials, and preparing the precursor powder through mechanical ball milling, vacuum drying, carbonization treatment, crushing and sieving. Then, the precursor powder is sprayed with plasma, and the precursor powder triggers self-reaction synthesis while passing through the high temperature zone of the plasma, and obtains spherical composite particles in which the TiC phase and the Fe phase are uniformly dispersed with each other.

A method for preparing spherical TiC/Fe cermet composite particles, comprising the following process steps:

1. Preparation of precursor powder: use cheap Ti/Fe powder and sucrose as raw materials, mix the powder according to the Ti:C atomic ratio of 1:1, perform mechanical ball milling with absolute ethanol as the medium, and grind the resulting slurry Carry out vacuum drying, and then carry out carbonization treatment under a nitrogen protective atmosphere, crush and sieve the obtained porous block to obtain a precursor powder;

2. Preparation of spherical TiC/Fe composite particles: Using inductively coupled plasma technology, after pre-evacuation, adjust the plasma process parameters to obtain a stable plasma torch; the obtained precursor powder is subjected to inductively coupled plasma spraying Processing: When the precursor powder passes through the plasma high-temperature zone, it absorbs heat rapidly and initiates self-reaction synthesis. Under the action of double heat, the powder melts and cools and solidifies into a spherical powder to obtain spherical TiC/Fe cermet composite particles.

The mechanical ball milling described in step 1, the ball-to-material ratio is 5:1, the ball milling time is 24-48 hours, and the obtained slurry is vacuum-dried at 120° C. for 12 hours. The dried powder is carbonized in a nitrogen protective atmosphere. The carbonization system is 250°C for 1h, 350°C for 2-4h, crushed and sieved to obtain the precursor powder.

The preparation of spherical TiC/Fe composite particles in step 2 is pre-evacuated to 1.0×10 ^-3 Pa by a diffusion pump unit to establish a stable operation of inductively coupled plasma. The main parameters are: power 40KW, argon gas flow rate 30~60slpm, argon side gas flow rate 100~200slpm, system negative pressure 1000~1200mm water column. Using argon as a carrier gas, the above-mentioned precursor powder is axially sent into the plasma high-temperature zone, the flow rate of the carrier gas is 3.5-10 slpm, and the powder feeding speed is 10-30 g/min.

The raw material used in the invention is Ti/Fe powder, and the cost is low; the carbon source is provided by sucrose, and the obtained amorphous carbon has high reactivity, and simultaneously acts as a binder.

Adopt above technical scheme, the advantage of the present invention is:

1. The raw materials are abundant and easy to obtain, and the cost is low.

2. The time is short, saving energy and reducing costs.

3. Using plasma technology to initiate self-reaction synthesis, the process is simple, the process is short, and the production efficiency is high.

4. The prepared metal-ceramic composite particles have good sphericity, compact structure, metal phase and ceramic phase are mutually dispersed and evenly distributed, and wettability is good.

Description of drawings

Figure 1 is a cross-sectional QBSD photo of the precursor powder.

Fig. 2 is a cross-sectional QBSD photo of spherical TiC/Fe composite particles prepared in the present invention.

detailed description

Example 1:

1. Preparation of precursor powder

Using Ti/Fe powder and sucrose as raw materials, according to the stoichiometric ratio of 1:1, carry out mechanical ball milling with anhydrous ethanol as the medium, the ball-to-material ratio is 5:1, and the ball milling time is 24 hours. Dry for 12h. The dried powder was carbonized in a nitrogen protective atmosphere. The carbonization system was 250°C for 1h, 350°C for 2h, crushed and sieved to obtain the precursor powder.

2. Preparation of spherical TiC/Fe composite particles

Pre-evacuate to 1.0×10 ^-3 Pa through the diffusion pump unit to establish a stable inductively coupled plasma. The main parameters are: power 40KW, argon working gas flow rate 35slpm, argon side gas flow rate 150slpm, system negative pressure 1000mm water column. Argon is used as the carrier gas to send the above precursor powder axially into the plasma high temperature zone, the flow rate of the carrier gas is 10 slpm, and the powder feeding rate is 10 g/min. The precursor powder absorbs heat and melts when passing through the high-temperature region of the plasma, and at the same time initiates self-reaction synthesis, and the molten droplets are finally condensed into spherical TiC/Fe composite particles under the action of surface tension.

Example 2:

1. Preparation of precursor powder

Using Ti/Fe powder and sucrose as raw materials, the stoichiometric ratio is 1:1, mechanical ball milling is carried out with absolute ethanol as the medium, the ball-to-material ratio is 5:1, and the ball milling time is 36 hours. Dry for 12h. The dried powder was carbonized in a nitrogen atmosphere. The carbonization system was 250°C for 1h, 350°C for 3h, crushed and sieved to obtain the precursor powder.

2. Preparation of spherical TiC/Fe composite particles

Pre-evacuate to 1.0×10 ^-3 Pa through the diffusion pump unit to establish a stable inductively coupled plasma. The main parameters are: power 40KW, argon working gas flow rate 60slpm, argon side gas flow rate 100slpm, system negative pressure 1100mm water column. Argon is used as the carrier gas to send the above precursor powder axially into the plasma high temperature zone, the flow rate of the carrier gas is 3.5 slpm, and the powder feeding rate is 15 g/min. The precursor powder absorbs heat and melts when passing through the high-temperature region of the plasma, and at the same time initiates self-reaction synthesis, and the molten droplets are finally condensed into spherical TiC/Fe composite particles under the action of surface tension.

Example 3:

1. Preparation of precursor powder

Using Ti/Fe powder and sucrose as raw materials, the stoichiometric ratio is 1:1, mechanical ball milling is carried out with absolute ethanol as the medium, the ball-to-material ratio is 5:1, and the ball milling time is 48 hours. Dry for 12h. Carbonize the dried powder in a nitrogen atmosphere. The carbonization system is 250°C for 1h, 350°C for 4h, crushed and sieved to obtain the precursor powder.

2. Preparation of spherical TiC/Fe composite particles

Pre-evacuate to 1.0×10 ^-3 Pa through the diffusion pump unit to establish a stable inductively coupled plasma. The main parameters are: power 40KW, argon working gas flow rate 60slpm, argon side gas flow rate 120slpm, system negative pressure 1200mm water column. Using argon as the carrier gas, the above-mentioned precursor powder was axially sent into the plasma high-temperature zone, the flow rate of the carrier gas was 5 slpm, and the powder feeding rate was 20 g/min. The precursor powder absorbs heat and melts when passing through the high-temperature region of the plasma, and at the same time initiates self-reaction synthesis, and the molten droplets are finally condensed into spherical TiC/Fe composite particles under the action of surface tension.

Claims (5)

1. a preparation method for spherical TiC/Fe cermet composite particles, is characterized in that: comprise following processing step:

1) preparation of precursor powder: with Ti/Fe powder and sucrose for raw material, the proportioning of powder is carried out according to Ti:C atomic ratio 1:1, be that medium carries out mechanical ball milling with absolute ethyl alcohol, gained slurry is carried out vacuum drying, then under nitrogen protection atmosphere, carry out carbonization treatment, gained cellular block is carried out fragmentation, sieving obtains precursor powder;

2) preparation of spherical TiC/Fe composite particles: utilize inductively coupled plasma technology, after forvacuum, each technological parameter of adjustment plasma, obtains the plasma torch of stable operation; Gained precursor powder is carried out the process of inductively coupled plasma meltallizing: precursor powder absorbs heat rapidly when passing plasma high-temperature district and causes autoreaction synthesis, powder melts under the effect of dual heat also gathers cold curing globulate powder, obtains spherical TiC/Fe cermet composite particles.

2. the preparation method of a kind of spherical TiC/Fe cermet composite particles according to claim 1, is characterized in that: step 1) described ball milling time material ball ratio 1:5, Ball-milling Time 24 ~ 48h; Vacuum drying temperature is 120 DEG C; Carbonization treatment system is: heating rate 5 DEG C/min, 250 DEG C of insulation 1h, 350 DEG C of insulation 2 ~ 4h.

3. the preparation method of a kind of spherical TiC/Fe cermet composite particles according to claim 1, is characterized in that: step 2) described inductively coupled plasma plays forearc, and carry out forvacuum by diffusion pump unit and reach 1.0 × 10 ^-3pa, prevents the oxidation of Ti/Fe and the reaction of C to run off.

4. the preparation method of a kind of spherical TiC/Fe cermet composite particles according to claim 1, it is characterized in that: step 2) described inductively coupled plasma, its main technologic parameters is: employing argon gas is work gas, limit gas and carrier gas, working gas flow 30 ~ 60slpm, limit throughput 100 ~ 200slpm, system negative pressure 1000 ~ 1200mm water column, powder carries throughput 3.5 ~ 10slpm, powder feed rate is 10 ~ 30g/min, equipment power output 40KW.

5. the preparation method of a kind of spherical TiC/Fe cermet composite particles according to claim 1, is characterized in that: cermet composite particles is of a size of 45 ~ 75 μm, is the spherical powder that the mutual dispersivity of metal/ceramic two-phase is good.