Physical and mechanical properties of ceramics based on ZrN-ZrO2 obtained by spark plasma sintering method

Abstract

Relevance. Increasing the service life of mining tools is an important task in the development of geology associated with the investigation of new ceramic materials for functional purposes. The ability to reduce wear and thermal and chemical effects of rocks on the working elements of mining equipment determines the vector of development of the use of super-hard, high-strength and refractory ceramics. At the same time, the task is set to increase the fracture toughness of the materials used to solve the problem of maintaining the operability of equipment under conditions of critical deformations. To accomplish this task, it is necessary to study the patterns of consolidation of ceramic materials and search for the optimal combination of consolidation parameters to achieve improved physical and mechanical properties. Aim. To develop a method for producing high-density durable ceramics based on commercially available zirconium nitride powders using spark plasma sintering under vacuum conditions, to study the phase composition and physical and mechanical properties of the resulting samples. Methods. X-ray phase analysis of the studied samples, nanoindentation, microscopic analysis. Results and conclusion. The authors have studied the physical and mechanical properties of zirconium nitride consolidated by spark plasma sintering at 2000℃, a pressure of 30–60 MPa and a holding time at a given temperature of 5–10 minutes. Qualitative and quantitative X-ray phase analysis was carried out, within which the content of the main phase of zirconium nitride and zirconium dioxide phase was determined. It was found that an increase in the pressure applied during consolidation and holding time contributes to better compaction and a decrease in the porosity of the samples from 8.52 to 2.72%. It was found that with a decrease in porosity, the elastic modulus increased in the range from 320 to 378 GPa, and the hardness from 7.3 to 10.4 GPa. At the same time, by extrapolating the data, it was established that non-porous zirconium nitride samples will have an elastic modulus of 394 GPa and a Martens hardness of 11.56 GPa. For the samples under study, critical stress intensity factors were determined. It was established that at a porosity of less than 5%, the critical stress intensity factor of zirconium nitride consolidated by spark plasma sintering has values of at least 4 MPa m1/2.