CN101759958B - A ceramic reinforced friction material and its preparation method - Google Patents

Abstract

The invention discloses a ceramic reinforced friction material and a preparation method thereof. Its main components are composed of thermosetting resin, resin curing agent, reinforcing fiber, friction performance modifier and filler, and reinforced ceramic powder; the reinforced ceramic powder Mainly use Al ₂ O ₃ , CaSiO ₃ , CaMgSi ₂ O ₆ as raw materials, add sintering aids such as CuO, MnO, TiO ₂ , CaO, MgO, B ₂ O ₃ to the above raw materials, and calcinate at a certain temperature to obtain Coarse ceramic powder particles. The invention uses ceramic powder particles with coarse crystal grains to strengthen the friction material, utilizes the unique wear resistance characteristics of the ceramic material, and effectively reduces the wear rate on the basis of stabilizing the friction coefficient of the friction material, thereby improving the service life of the friction material. The ceramic enhanced friction material of the invention can be widely used in the preparation of motor vehicle brake pads, machine tool and electrode brakes, clutch linings and the like.

Description

A ceramic reinforced friction material and its preparation method

technical field

The invention relates to a friction material and a preparation method thereof, in particular to a preparation method of friction materials used for motor vehicle brake pads, machine tool and electrode brakes, clutch linings and the like.

Background technique

Friction materials for automobile braking, commonly known as brake pads, are one of the most important safety components in the automobile braking system, and are related to the safety of the life and property of automobile drivers. The preparation of brake pads is generally made of resin, reinforcing fiber, friction performance modifier and filler, etc., which are uniformly mixed, hot-pressed and cured. In order to improve the braking performance of friction materials, reinforcing fibers and friction performance regulators have been extensively studied, and have become a research hotspot of friction materials at present.

Traditional brake pads mainly use asbestos fibers as the reinforcement phase. Since asbestos was found to be an important carcinogen, semi-metallic friction materials with metal fibers as the reinforcement phase have been developed rapidly and have been widely used in the manufacture of various vehicles. However, the semi-metallic friction material has the disadvantage of being easy to rust. In order to improve the friction performance and avoid the degradation of the braking performance of semi-metallic friction materials due to the corrosion of metal fibers, slag fibers, aramid fibers, ceramic fibers, carbon fibers, etc. have been gradually applied. However, the above-mentioned aramid fibers, ceramic fibers, and carbon fibers with better performance are more expensive, which leads to a sharp increase in the production cost of high-performance friction materials.

In order to improve the friction and wear performance on the basis of reducing the production cost of friction materials, friction performance regulators have been extensively studied and become one of the important ways to improve the performance of friction materials. Friction modifiers are substances added to friction materials that can improve the friction coefficient and wear rate, and are mainly divided into two categories: lubricants and abrasives. The main purpose of the lubricant is to reduce the change of the coefficient of friction during braking. Commonly used lubricants include graphite and various types of metal sulfides; abrasives are mainly hard particles of metal oxides, quartz powder and silicate compounds. Commonly used abrasives mainly include alumina, silicon carbide, silicon dioxide, zirconium oxide, zirconium silicate, and chromium oxide. Research by Boz M et al. on Tribology International (2007, 40(7): 1161-1169) found that adding alumina to friction materials can increase the friction coefficient and reduce the wear rate. The research published by MatejkaV et al. in the Wear magazine shows that adding silicon carbide to the friction material can greatly improve the friction coefficient, while the wear rate only increases slightly; Jang H et al. published in Wear (2000, 239 (2): 229 The research on -236) found that a certain amount of antimony trisulfide and zirconium silicate powder has a great influence on the friction coefficient and stability of automobile brake pads. However, the current research on friction modifiers mainly focuses on the selection of different materials, and there are very few reports on the research and industrial application of powders with different hardness and particle size for the same material system. The designer of the present invention has found through experiments that coarse ceramic powder particles have better friction-increasing performance than powders with fine particle diameters.

Contents of the invention

The purpose of the present invention is to provide a method of adding sintering aids to the powder, and then calcining at a certain temperature to obtain coarse ceramic powder particles, and then use the ceramic powder particles with coarse grains as a friction performance regulator to enhance Preparation method of friction material.

The ceramic reinforced friction material proposed by the present invention has the parts by weight as follows:

Thermosetting resin 5-20 parts

Resin curing agent 0.05～5 parts

Reinforced fiber 15-40 parts

Friction modifier and filler 30-70 parts

Al ₂ O ₃ based ceramic powder 0.01～15 parts

CaSiO ₃ based ceramic powder 0.01～15 parts

CaMgSi ₂ O ₆ based ceramic powder 0.01～15 parts

The preparation method of the ceramic reinforced friction material proposed by the present invention mainly includes the following processes:

1) First, Al ₂ O ₃ , CaSiO ₃ , CaMgSi ₂ O ₆ are used as raw materials, and sintering aids such as CuO, MnO, TiO ₂ , CaO, MgO, B ₂ O ₃ are added to the above raw materials, and calcined at a certain temperature Finally, coarse ceramic powder particles are obtained. Add 0.01-2 parts of CuO, 0.01-2 parts of MnO, 0.01-2 parts of CaO, 0.01-2 parts of MgO, and 0.1-5 parts of TiO ₂ to 100 parts of Al ₂ O ₃ powder, mix and stir evenly Afterwards, it is calcined at 1100-1300°C for 1-6 hours, cooled and crushed to obtain Al ₂ O ₃ -based ceramic powder. Add 0.01-5 parts of ZnO, 0.01-5 parts of MgO, and 0.5-10 parts of B ₂ O ₃ to 100 parts of CaSiO ₃ powder, mix and stir evenly, and calcinate at 1000-1200°C for 1-6 hours, after cooling Pulverize to obtain CaSiO ₃ -based ceramic powder. Add 0.01-5 parts of ZnO, 0.01-5 parts of Li ₂ O, 0.5-10 parts of B ₂ O ₃ to 100 parts of CaMgSi ₂ O ₆ powder, mix and stir evenly, and calcinate at 1000-1200°C for 1-6 Hours, cooled and pulverized to obtain CaMgSi ₂ O ₆ based ceramic powder.

2) Mix and stir the thermosetting resin, resin curing agent and reinforcing fiber for 1 to 3 hours, then introduce the Al ₂ O ₃ -based ceramic powder, CaSiO ₃ -based ceramic powder and CaMgSi ₂ O ₆ -based ceramic powder and mix and stir for 0.5 ~ 3 hours, finally introduce the friction modifier and filler and mix and stir for 1 ~ 3 hours; press the above-mentioned uniformly mixed and stirred composite material into a green body, and then press at 150 ~ 170 ° C and 15 ~ 25 MPa pressure for 6 ~ 20 minutes, and then heat treatment at 170-190° C. for 6-15 hours to obtain the ceramic reinforced friction material of the present invention.

In the present invention, the thermosetting resin may be one or more of phenolic resin, boron modified phenolic resin, melamine modified phenolic resin and aralkyl modified phenolic resin.

Said resin curing agent can be one or more of hexamethylenetetramine, sulfur and urotropine.

Said reinforcing fiber can be one or more of asbestos, steel fiber, slag fiber, glass fiber, aramid fiber, ceramic fiber and carbon fiber.

Said friction modifier and filler can be one or more of molybdenum disulfide, talc, mica, tin chloride, graphite, barite, wollastonite, vermiculite, tire powder, alumina and silicon micropowder. kind.

The present invention has the following beneficial effects:

The preparation process of the present invention is simple, by adding sintering aids such as CuO, MnO, TiO ₂ , CaO, MgO, B ₂ O 3 to Al ₂ O ₃ , CaSiO ₃ , CaMgSi _{2 O 6} raw materials, after calcining at a certain temperature Coarse ceramic powder particles are obtained, and then the friction material is reinforced with coarse ceramic powder particles, and the unique wear resistance characteristics of ceramic materials are used to effectively reduce the wear rate on the basis of stabilizing the friction coefficient of the friction material, thereby Increase the service life of the friction material.

Detailed ways

The present invention will be further described below in conjunction with example.

Example 1:

Add 0.3 parts of CuO, 0.1 parts of MnO, 0.1 parts of CaO, 0.01 parts of MgO, and 3 parts of TiO ₂ to 100 parts of Al ₂ O ₃ powder, mix and stir evenly, and calcinate at 1200°C for 2 hours, after cooling Pulverize to get Al ₂ O ₃ based ceramic powder. Add 2 parts of ZnO, 2 parts of MgO, and 4 parts of B ₂ O ₃ to 100 parts of CaSiO ₃ powder, mix and stir evenly, calcinate at 1100°C for 2 hours, cool and pulverize to obtain CaSiO ₃ -based ceramic powder . Add 2 parts of ZnO, 2 parts of Li ₂ O, and 4 parts of B ₂ O ₃ to 100 parts of CaMgSi ₂ O ₆ powder, mix and stir evenly, calcinate at 1100°C for 2 hours, cool and pulverize to obtain CaMgSi ₂ O ₆ based ceramic powder.

Weigh 10 parts of phenolic resin, 0.2 parts of hexamethylenetetramine, 5 parts of steel fiber, 10 parts of aramid fiber, and 5 parts of ceramic fiber, mix and stir for 2 hours; then add the Al ₂ O ₃ based ceramic powder prepared above 1 part, 0.5 parts of CaSiO _3- based ceramic powder and 0.5 part of CaMgSi ₂ O ₆ -based ceramic powder, mixed and stirred for 1 hour; then added 1.5 parts of molybdenum disulfide, 4 parts of graphite, 16 parts of barite, 5 parts of wollastonite, 4 parts of tire powder, mixed and stirred for 2 hours. The uniformly mixed and stirred composite material was pressed into a green body, then molded at 160°C and 20MPa for 15 minutes, and then heat-treated at 180°C for 10 hours to obtain the ceramic reinforced friction material of the present invention.

Example 2:

Add 0.5 parts of CuO, 0.05 parts of MnO, 0.05 parts of CaO, 0.02 parts of MgO, and 2.5 parts of TiO ₂ to 100 parts of Al ₂ O ₃ powder, mix and stir evenly, and calcinate at 1250°C for 3 hours, after cooling Pulverize to get Al ₂ O ₃ based ceramic powder. Add 3 parts of ZnO, 3 parts of MgO, and 5 parts of B ₂ O ₃ to 100 parts of CaSiO ₃ powder, mix and stir evenly, calcinate at 1050°C for 3 hours, cool and pulverize to obtain CaSiO ₃ -based ceramic powder . Add 3 parts of ZnO, 3 parts of Li ₂ O, and 5 parts of B ₂ O ₃ to 100 parts of CaMgSi ₂ O ₆ powder, mix and stir evenly, calcinate at 1050°C for 3 hours, cool and pulverize to obtain CaMgSi ₂ O ₆ based ceramic powder.

Weigh 15 parts of melamine-modified phenolic resin, 0.1 part of hexamethylenetetramine, 0.2 part of urotropine, 8 parts of aramid fiber, 5 parts of ceramic fiber, and 5 parts of pitch carbon fiber, mix and stir for 3 hours; then add 0.5 parts of _{Al2O3 -} based ceramic powder prepared above, 1 part of _CaSiO3- based ceramic powder and _0.5 part of _CaMgSi2O6 -based ceramic powder, mixed and stirred for 1 hour; then added 5 parts of molybdenum disulfide to the above mixture , 15 parts of graphite, 30 parts of barite, 10 parts of talc, 5 parts of vermiculite, mixed and stirred for 2 hours. The uniformly mixed composite material was pressed into a green body, then molded at 165°C and 18MPa for 10 minutes, and then heat-treated at 175°C for 12 hours to obtain the ceramic reinforced friction material of the present invention.

Example 3:

Add 0.3 parts of CuO, 0.2 parts of MnO, 0.1 parts of CaO, 0.1 parts of MgO, and 3 parts of TiO ₂ to 100 parts of Al ₂ O ₃ powder, mix and stir evenly, and calcinate at 1200°C for 1.5 hours, after cooling Pulverize to get Al ₂ O ₃ based ceramic powder. Add 2.5 parts of ZnO, 2.5 parts of MgO, and 5 parts of B ₂ O ₃ to 100 parts of CaSiO ₃ powder, mix and stir evenly, calcinate at 1150°C for 2.5 hours, cool and pulverize to obtain CaSiO ₃ -based ceramic powder . Add 3.5 parts of ZnO, 3.5 parts of Li ₂ O, and 6 parts of B ₂ O ₃ to 100 parts of CaMgSi ₂ O ₆ powder, mix and stir evenly, calcinate at 1100°C for 1.5 hours, cool and pulverize to obtain CaMgSi ₂ O ₆ based ceramic powder.

Weigh 12 parts of aralkyl modified phenolic resin, 0.2 part of hexamethylenetetramine, 0.1 part of urotropine, 5 parts of glass fiber, 5 parts of aramid fiber, and 20 parts of pitch carbon fiber, and mix and stir for 1.5 hours; Then add 1 part of _{Al2O3 -} based ceramic powder prepared above, 0.1 part of _CaSiO3 -based ceramic powder and _0.1 part of _CaMgSi2O6 -based ceramic powder, mix and stir for 1.5 hours; Molybdenum sulfide, 12 parts of graphite, 28 parts of barite, 12 parts of talc, 5 parts of vermiculite, 6 parts of tire powder, mixed and stirred for 2 hours. The uniformly mixed composite material was pressed into a green body, then molded at 170°C and 18MPa for 8 minutes, and then heat-treated at 180°C for 10 hours to obtain the ceramic reinforced friction material of the present invention.

According to the national standard GB5763-1998, the friction material prepared above was tested on the friction coefficient and wear rate on a constant speed friction testing machine. The specific test results are shown in the following table:

It can be seen from the above table that the friction coefficient of the product of the present invention is stable, especially the wear rate is far lower than the national standard requirement, and does not change much with the increase of temperature. This shows that the present invention uses ceramic powder particles with coarse crystal grains to strengthen the friction material, utilizes the unique wear resistance characteristics of ceramic materials, and can effectively reduce its wear rate on the basis of stabilizing the friction coefficient of the friction material, thereby improving the wear resistance of the friction material. service life.

Claims (2)

1. enhanced ceramic friction material is characterized in that parts by weight are formed to comprise:

Above-mentioned described thermosetting resin is one or more in resol, boron modified phenolic resin, cyanurotriamide modified resol and the aralkyl modified phenolic resins; Described resin curing agent is one or more in hexamethylenetetramine, sulphur and the urotropine; Described fortifying fibre is one or more in asbestos, steel fiber, slag fibre, glass fibre, aramid fiber, ceramic fiber and the carbon fiber; Described frictional property regulator and filler are one or more in molybdenumdisulphide, talcum, mica, tin chloride, graphite, barite, wollastonite, vermiculite, tyre talc, aluminum oxide and the silicon powder;

Described Al ₂O ₃The preparation process of based ceramic powder body is as follows: to 100 parts of Al ₂O ₃Add 0.01～2 part CuO, 0.01～2 part MnO, 0.01～2 part CaO, 0.01～2 part MgO, 0.1～5 part TiO in the powder ₂, 1100～1300 ℃ of calcinings 1～6 hour, pulverized the cooling back, promptly gets Al after the mixing and stirring ₂O ₃The based ceramic powder body;

Described CaSiO ₃The preparation process of based ceramic powder body is as follows: to 100 parts of CaSiO ₃Add 0.01～5 part ZnO, 0.01～5 part MgO, 0.5～10 part B in the powder ₂O ₃, 1000～1200 ℃ of calcinings 1～6 hour, pulverized the cooling back, promptly gets CaSiO after the mixing and stirring ₃The based ceramic powder body;

Described CaMgSi ₂O ₆The preparation process of based ceramic powder body is as follows: to 100 parts of CaMgSi ₂O ₆Add 0.01～5 part ZnO, 0.01～5 part Li in the powder ₂O, 0.5～10 part B ₂O ₃, 1000～1200 ℃ of calcinings 1～6 hour, pulverized the cooling back, promptly gets CaMgSi after the mixing and stirring ₂O ₆The based ceramic powder body.

2. the preparation method of an enhanced ceramic friction material is characterized in that comprising the steps: at first thermosetting resin, resin curing agent and fortifying fibre being mixed stirring 1～3 hour, then with Al ₂O ₃Based ceramic powder body, CaSiO ₃Based ceramic powder body and CaMgSi ₂O ₆The based ceramic powder body is introduced also to mix and was stirred 0.5～3 hour, at last frictional property regulator and filler is introduced and is mixed and stirred 1～3 hour; The matrix material of above-mentioned mixing and stirring is pressed into base substrate, and mold pressing 6～20 minutes under 150～170 ℃, the pressure of 15～25MPa then promptly got enhanced ceramic friction material of the present invention in 6～15 hours 170～190 ℃ of following thermal treatments again.