Stress Analysis Of Ceramic/Metal Gradient Wear-Resistant Coating

Wear is one of the three types of material failure. As we all know, it makes huge economic loss. In the same time, abrasive wear is the major failure reason in mining machines. Therefore, it's an essential task for us to research the principle of abrasive wear, find the reasons of abrasive wear and invent a kind of effectively and economically method.Utilizing new type of ceramic composite powders or materials and combining thermal spraying technology, especially plasma-spraying technology, we can produce metal systematically. And the research on it has become an important branch of composite material technology and high-tech producing area.Because of the difference of physical property between ceramic and metal, it is easy to cause great residual thermal stress in the ceramic coating. In the meantime, the ability against mechanical stress of c material is an important index to estimate the quality of the coating. In this thesis, author analyzed the residual thermal stress and the mechanical stress of the composite wear-resistant material with substrate of cast iron and plasma-sprayed ceramic or carbide coating. And the residual thermal stress had been calculated by ANSYS software. In the meantime, author demonstrated the working stress of coating qualitatively consulting some relevant information.Considering the working conditions of the mining machines, author select the material for wear-resistant coating. According to the demand for property experiments, author designed the size and structure of the specimen and made the wear-resistant specimen by plasma spray technology in which the substrate is made of common cast iron, the bound layer is made of NiCrAl and the working layer is sprayed by powders of 20%of WC and 80%of NiCrAl or 60%of A12O3 and 40% of TiOa- And that, the thickness of coating is 0.3mm or 0.5mm respectively.With the wide usage of slurry pumps in mining machines, the problem of abrasive wear is being concerned increasingly by users and manufactures. From this paper, and effective method could be seen, plasma spraying technology, which can solve the problem. That is, by spraying wear-resistant gradient coating of ceramic/metal composite materials on the components of the slurry pumps, which aresubject to running fluid, such as vanes and volutes, the wear rate can be highly reduced. Furthermore, this technology can be applied on all the wearing mining machines. Therefore, the residual thermal stress in the wear-resistant coatings on the slurry pumps' front guard plate is analyzed and the improved scheme is put forward. And the preliminary analysis of its working stress is carried out through ANSYS/LS-DYNA computing method.