Litus K. Development and Use of the Efficient Thermochemical Treatment Procedure of Articles in Powder Mixtures

The aim and the problems of the investigation. The aim of this thesis is the acceleration and reduction of prices of nitriding and boriding using new saturation mixtures and procedures not requiring complex equipment. The main problems: to propose the new not costly saturating mixtures for nitriding and boriding; to investigate the role of the procedures parameters and to choose their optimal values; to elaborate the new process of the low-temperature nitriding of titanium alloys; to study the microbrittleness corrosion and wear resistance of the peaces after new termochemical treatment (TCT), to estimate its efficiency and to justify the practical recommendation. The object of the investigation - the processes of steels and titanium alloys saturation by N and B. the subject of the investigation - the elaboration of effective procedures and techniques using the new nanosized powder mixtures TCT for acceleration and simplification saving high operational properties. The methods of investigation: optical and electron microscopy, X-rays analysis, microhardness, microbrittleness, corrosion and wear resistance testing. The experimental results were statistically processed. The scientific novelty of results: 1. It is shown that the proposed new saturating nano-sized mixtures accelerate nitriding by 10 times and boriding by 2-3 times. 2. It is established that nitriding in С3H6N6 unlike the traditional process in NH3, elevates the rate of nitriding case growth with the increase of carbon and alloying elements amount due to diffusion acceleration and the elimination of continuous - and -faces layer formation. 3. using the high active saturating nano-sized medium allowed to decrease the nitriding temperature of Ti alloys to 550-600 ?C. the nitriding rate increases by 20 % in the presence of oxides. Practical importance of results the new mixture for steels and Ti alloys nitriding is proposed (the patent of Ukraine № 42478); the low-temperature nitriding of Ti alloy combining the aging process is elaborated new mixture for boriding is offered (the patent of Ukraine № 33654). The obtained results are adopted for realization on the state enterprise "The Kharkov tractor plant" and enter price "Dakon" (Krementshug). The proposed methods are used in the educational process of NTU "KhPI" and KhNAHU. The branch of using - machine building.