Ti3SiC2-layered ceramic material

In recent years, material scientists have synthesized a new class of 312 ceramic materials, whose general formula is M3XZ2, in which M is one or several transition metal elements (such as Ti, V, etc.), X is one or several main group elements, multiple III and IV main group elements (such as Al, Ge, Si, etc.),  Z is one or several non-metallic elements (such as C, N, B, etc.). The 312-sex ternary compounds studied at present mainly include Ti3SiC2, Ti3AlC2, Ti3GeC2.  They have the same crystal structure and belong to the P63/ MMC space group.  A typical example of this class of compounds is Ti3SiC2.  

What is Ti3SiC2 layered ceramic material?

Titanium silicon carbide Ti3SiC2 (Titanium silicon Carbide) is a comprehensive ceramic material, not only has high temperature resistance, oxidation resistance, high strength performance, but also metal materials conductive, thermal conductivity, machinability, plastic etc..  The development opportunity of this material was roughly in the 1980s, because of the rapid development of fiber, whisker and other reinforcers and the requirements of aviation engines with high thrust-to-weight ratio, ceramic matrix composites became the research focus.  The toughness is improved by fiber and whisker reinforcement, but it is still difficult to be applied because of high preparation cost and poor reliability. To solve this problem, researchers began to explore high-temperature materials with both metal and ceramic properties, and finally found a titanium silicon carbide (Ti3SiC2) in the Ti-Si-C system.  Ti3SiC2 has the characteristics of metal, has good thermal conductivity and electrical conductivity at room temperature, relatively low Vickers hardness and high elastic modulus;  Malleable at room temperature, can be processed like metal, plastic at high temperature;  At the same time, it has the properties of ceramic materials, with high yield strength, high melting point, high thermal stability and good oxidation resistance, can maintain high strength at high temperature.  What is more significant is that it has lower friction coefficient and better self-lubricating performance than traditional solid lubricant graphite and molybdenum disulfide.  

Main properties of Ti3SiC2 layered ceramic materials

Ti3SiC2 combines the characteristics of ceramic and metal, high elastic modulus, high melting point and high temperature stability reflect similar ceramic properties;  The high conductivity, high elastic modulus, high melting point and high temperature stability reflect the ceramic like properties.  

The damage resistance of Ti3SiC2 shows that there is a large pseudo-plastic damage zone in the subsurface under the indentation.  The reason is that Ti3SiC2 has multiple energy absorption mechanisms during contact damage, such as diffusion microcrack, crack deflection, grain pulling out, grain bending, etc.  Moreover, this kind of material has good self-lubrication.  This material has a wide application prospect as high temperature structural material, brush material, self-lubricating material, heat exchange material and so on.  However, the relatively low hardness, wear resistance and low oxidation resistance of other ceramic materials limit its application in sensitive occasions such as fatigue resistance, wear resistance and oxidation resistance.  

Application of Ti3SiC2 layered ceramic materials  

1. Biomedical applications  

In dentistry, materials or components used in the oral environment can not only withstand long-term oxidation, maintain stability, but also need to have good processability and plasticity.  Ti3SiC2 has both the properties of ceramic material and metal properties, as well as good biocompatibility, making it possible to apply it to human body.  Ti3SiC2 can be processed into precisely sized threads without lubricant, so it can be made into implants or prostheses for clinical application in oral medicine.  The elastic modulus of Ti3SiC2 is closer to enamel or dentin than zirconia (1.9×105MPa), which increases the potential of Ti3SiC2 to be used in post or porcelain dental crowns.  The Ti3SiC2 material obtained from self-propagating high temperature contains porous tissue, which may be easier to organize and bind to it.  The low friction coefficient makes it possible to use it in orthodontics to increase slippability and reduce friction resistance.  Corrosion resistance and oxidation resistance are important conditions for the material to be applied in oral environment and maintain its stability.  The material and porcelain powder are both ceramic materials, and the combination degree may be better than that of metal and porcelain. Therefore, the application scope of porcelain internal crown may be wider.  

However, in the currently known preparation methods of Ti3SiC2, it is necessary to improve the preparation process to get pure Ti3SiC2 blocks, so as to understand more accurate properties of the material.  Further laboratory and clinical studies are needed to confirm the biocompatibility and oral clinical practicability of the material.  

2. The application of refractory materials  

With the popularization of rapid firing technology in ceramic industry, the cycle cycle of kiln furniture is shorter and shorter, and the use conditions are more demanding. Therefore, it is necessary to 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 advanced refractory material, the quality of kiln furniture has an important influence on the quality of fired products.  Ti3SiC2 ceramic material is not sensitive to thermal shock, and its unique layered structure and plastic behavior at high temperature can alleviate the action of thermal stress.  After thermal shock of △T=1400℃, the residual strength of the material is still above 300MPa, and the thermal shock resistance of the best can withstand the temperature difference of 900℃.  At the same time, Ti3SiC2 ceramic material has the advantages of good chemical corrosion resistance, easy processing, low raw material relative cost, which makes it an ideal kiln material to be developed.