Abstract: A multilayer coating of metal-cutting tools is composed of alternating layers of two components. One of these is a nitride or carbide of a metal of group IV. The other is a nitride, carbide, boride or silicide of a metal of group VI. The layer thickness of the group IV metal compound is from 0.05 to 0.5 .mu.m, and the layer thickness of the group VI metal compound constitutes 15 to 40 percent of the layer thickness of the group IV metal compound. The multilayer coating is preferably intended for application to metal-cutting tools used for machining high-alloyed materials.

Abstract: The apparatus comprises a consumable cathode (1) having a working end face (3), a solenoid (4) coaxially disposed relative to the consumable cathode (1) and having a tubular anode (5) received therein, an igniting electrode (6). Solenoid (4) encircles the tubular anode (5) and the consumable cathode (1), the number of turns per unit length of the solenoid (4) around the consumable cathode (1) being greater than the number of turns per unit length in the remaining portion of the solenoid (4).Moreover, the solenoid (4) extends beyond the igniting electrode (6) at the side opposite to the working end face (3) by a length exceeding half the length of the portion of the solenoid (4) disposed around the consumable cathode (1).

Abstract: A plasma arc apparatus comprises a working anode chamber in the form of a pipe of a non-magnetic metal, a consumable cathode provided with an opening for a work to be installed therein, the cathode having a cross-sectional configuration which coincides with that of this pipe, a starting electrode connected with the cathode and current sources for starting and feeding an arc between the anode and cathode. The cathode is disposed within the anode in axial relation therewith so that the lateral surface of the cathode faces the anode and functions as an evaporation surface whose width is less than the length of the anode. On the outer side of the anode there is mounted a magnetic system for deviating ions of the plasma produced by the arc in the direction of the work.

Abstract: A cutting tool hardening method, according to which a tool to be hardened is heated in air to a temperature of 130.degree. to 560.degree. C. in order to produce an oxide film 200 to 10,000 .ANG. thick on its surface which is then coated with a wear-resistant material by vacuum deposition.

Abstract: Cutting tools according to the invention are provided with a wear-resistant coating of heat-resistant compounds of high-melting metals. A layer of a pure metal is provided between the base material and the coating. The base material is a ceramic or an aluminum oxide-based metal-ceramic material. The intermediate layer is discontinuous. Such tools are manufactured by using condensation of plasma material and ion bombardment in order to successively deposit an intermediate layer of a pure metal and a coating of heat-resistant compounds of high-melting metals on the surface of the base material. The intermediate layer is deposited at a temperature of 1/2T.sub.S >T>1/3T.sub.S, where T.sub.S is the melting temperature of the metal being deposited and T is the temperature of the tool in .degree. K. The condensation rate and the duration of deposition are selected bearing in mind that metal is to be deposited only on defects found on the surface of the base material.

Abstract: An arc plasma generator comprises a consumable cathode, a cylindrical anode, and a focusing solenoid arranged coaxially with the consumable cathode. A power unit for maintaining the arc is electrically connected to the consumable cathode and the anode. In accordance with the invention the arc plasma generator further comprises a tubular plasma guide connected to an end face of the anode and an electromagnet. The electromagnet is arranged in the tubular plasma guide on the axis thereof and is enclosed in a housing made of a nonmagnetic material and having a cross-sectional area sufficient to conceal the cathode from the viewer's sight, looking in the direction of the cathode through the plasma guide. Also, the focusing solenoid is arranged on the tubular plasma guide and is connected in opposition with the coil of the electromagnet. A plasma arc apparatus for treating the surfaces of work-pieces comprises an arc plasma generator of the invention and an assembly for holding the work-piece to be treated.

Abstract: The dental prosthesis comprises a base from a durable corrosion-resistant metallic alloy and at least one external decorative layer. The external decorative layer is made of a harder material than the base and comprises nitrides, oxynitrides, carboxynitrides, cyanonitrides and/or oxides of metals of the subordinate subgroup of Group IV of the periodic system. The thickness ratio of the external decorative layer to the base is equal to 1:10-200 respectively.In the case where the dental prosthesis base comprises a structure of soldered members from a durable corrosion-resistant metallic alloy, the method for making the dental prosthesis comprises manufacture of the base by soldering members of the dental prosthesis from the abovementioned alloy into an integrated structure. Then the zone of the soldered juncture or the entire structure is coated, by electroplating or vacuum technique, with an additional layer from cobalt, nickel, molybdenum, chromium or zirconium, or from nitrides of chromium or molybdenum.

Abstract: A coating for a metal-cutting tool consisting of 90 to 70 wt. % of titanium nitride and 10 to 30 wt. % of chromium nitride or 3 to 18 wt. % of aluminium nitride, 2 to 8 wt. % of molybdenum nitride, 2 to 10 wt. % of chromium nitride, 0.5 to 10 wt. % of silicon nitride, taken in combination and uniformly distributed within the volume of the coating, titanium nitride being the balance.The coating is intended predominantly for application to metal-cutting tools when working stainless steels and refractory alloys.