In recent years, a materials scientist synthesized a new class of 312 type ceramic material, the general formula for M3XZ2, among them, the M is one or several of the transition metal elements (such as Ti, V), X is one or more of the following main group element, a number of III, IV main group elements (such as Al Ge Si), Z is one or several nonmetallic elements (such as C N B, etc.), there are 312 sex of the study of the ternary compound Ti3SiC2 main Ti3AlC2 Ti3GeC2 they have the same crystal structure, the same about/MMC space group
Typical representative of these compounds is a what Ti3SiC2 is layered Ti3SiC2 ceramic material Titanium silicon carbide Ti3SiC2 (Titanium silicon carbide) is a kind of composite ceramic material, has the performance of resistance to high temperature oxidation resistance of high strength, and metal materials such as the conductive machinability of thermal conductivity and plastic materials development opportunity in the 1980 s, roughly due to the rapid development of the strengthening agent such as fiber, whisker and aviation high in esteem than the requirements of the engine, ceramic matrix composites become the research hot spotBy fiber, whisker enhanced its toughness is improved, but because of the preparation of high cost and poor reliability, are still difficult to apply in order to solve this problem the researchers began to explore the nature of both metal and ceramic material of high temperature, finally found in Ti - Si - C system a titanium silicon carbide Ti3SiC2 (Ti3SiC2) has both the characteristics of metal at room temperature with good thermal conductivity and electrical conductivity, relatively low vickers hardness and high modulus of elasticity;Ductile at room temperature, can be processed like a metal, and plastic at high temperatures;At the same time, it has the properties of ceramic materials, high yield strength, high melting point, high thermal stability and good oxidation resistance. It can maintain high strength at high temperature. What is more significant is that it has lower friction coefficient and good self-lubrication performance than the traditional solid lubricant.
As early as in December 2005, the state Ministry of Science and Technology in our country has issued a dynamic said: one with independent intellectual property rights, Ti3SiC2 conductive ceramic production of a new generation of high-speed train pantograph slide in the national 863 program, high performance structural material technical topics, domestic developed with funding from the project to undertake unit Beijing jiaotong university after two years in succession to conquer the high-purity Ti3SiC2, Ti3AlC2, Ti2SnC ceramic powder bulk synthesis technology, skateboard manufacture process, to complete the study of physical and chemical properties, skateboarding loading test run. The Ti3SiC2 series ceramic skateboards successfully developed by this research group are featured with high conductivity, impact resistance, abrasion resistance, arc ablation resistance, low abrasion of the contact wire, etc., effectively solving the problems such as fast abrasion of the carbon based and powder metallurgy skateboards used at home and abroad, easy to break, and great damage to the contact wire. Ti3SiC2 ceramic skateboards successfully developed in that year played an important role in the development of high-speed railway in China.Ii.
Main properties of Ti3SiC2 layered ceramic materials
Ti3SiC2 combines the properties of ceramics and metals. Its high elastic modulus, high melting point and high temperature stability reflect similar ceramic properties. High conductivity, high elastic modulus, high melting point and high temperature stability reflect its similar ceramic properties.
Table 1. Main Properties of Ti3SiC2 ceramics (Room temperature)
Studies on the damage resistance of Ti3SiC2 show that there is a large pseudo-plastic damage zone under the indentation of Ti3SiC2. The reason is that Ti3SiC2 has multiple energy absorptionmechanisms during contact damage, such as diffusion microcrack, crack deflection, grain pull out, grain bending, etc. Moreover, this kind of material has good self-lubricity. This kind of material has wide application prospect as high temperature structure material, electric brush material, self-lubricating material, heat exchange material and so on. However, the relatively low hardness, wear resistance and oxidation resistance of ceramic materials limit its application in sensitive occasions such as fatigue resistance, wear resistance and oxidation resistance.
Iii. Application of Ti3SiC2 layered ceramic materials
(I) Biomedical applications
In dentistry, materials or components used in the oral environment are required to be both stable and processable over a long period of time due to oxidation. Ti3SiC2 has both ceramic and metal properties and good biocompatibility, making it possible to be used in human body. Ti3SiC2 can be processed into threads of precise size without lubricant, so it can be made into implants or prosthetics for clinical use in stomatology. Ti3SiC2's elastic modulus is closer to enamel or dentin than zirconia (1.9×105MPa), increasing its potential for application to post or ceramic internal crowns. Ti3SiC2 materials derived from self-propagating high-temperature materials contain porous tissue that may be easier to organize and bind to. The low coefficient of friction makes it possible to apply it to orthodontics to increase slippage and reduce frictional resistance. Corrosion resistance and oxidation resistance are important conditions for the application of this material in oral environment and for its stability. This material and porcelain powder are both ceramic materials, and their binding degree may be better than that of metal and porcelain. Therefore, the application scope of this material may be wider for the ceramic internal crown.
However, in the current known preparation method of Ti3SiC2, the preparation process must be improved to obtain pure Ti3SiC2 blocks, so as to understand more and more accurate properties of the material. Further laboratory and clinical studies are needed to confirm the biocompatibility and practicability of the material.
(2) applications in refractory materials
With the popularization of rapid firing technology in ceramic industry, the use cycle of kiln furniture is becoming shorter and the use conditions are more stringent. Therefore, it is necessary to continuously improve the thermal shock resistance of kiln furniture materials to meet the development needs of rapid firing technology in ceramic industry. As a kind of high - grade refractory, kiln furniture has important influence on the qualityof fired products. Ti3SiC2 ceramics are not sensitive to thermal shock, their unique layered structure and plastic behavior at high temperature can alleviate the effect of thermal stress. Material through △T=1400℃ thermal shock residual strength is still above 300MPa, thermal shock resistance performance of the best can withstand 900℃ temperature difference. At the same time, Ti3SiC2 ceramics has the advantages of good chemical resistance, easy processing and low relative cost of raw materials, making it an ideal kiln furniture material to be developed.
Honesty is the foundation
Gewang village, Daxue Township, Taihe District, Jinzhou City