Composite technique of preparing lacunaris titanium coating by using cold spraying and vacuum sintering

Abstract

The present invention discloses composite cold spraying and vacuum sintering process for preparing porous titanium coating. Mixed titanium-magnesium powder is first sprayed onto the roughened titanium or titanium alloy substrate to form composite titanium-magnesium coating, which is then sintered at high vacuum and high temperature to obtain porous titanium coating. Thus produced porous titanium coating has no oxide, thickness greater than 0.5 mm, opened and communicated pore structure, pores of 30-200 microns, porosity of 30-65 %, and metallurgical combination with the substrate with combination strength higher than 60MPa and elastic modulus adjustable in 30-50 GPa. The present invention is suitable for making bearing hard tissue implant, such as artificial joint, artificial bone, artificial tooth root, etc. with improved long term stability.

Description

technical field [0001] The invention relates to a preparation process of a titanium-based medical implant surface (such as a titanium and titanium alloy dental implant and a bone implant), in particular to a composite process for preparing a porous titanium coating by cold spraying and vacuum sintering. Background technique [0002] Titanium and its alloys are widely used in the repair and replacement of implants for damaged hard tissues due to their excellent biocompatibility, corrosion resistance and high specific strength. However, the poor long-term stability of the interface between the titanium-based implant and the host bone and the loosening of the implant caused by the mismatch of the elastic modulus are two major problems in clinical application. The method to solve the above problems is to compound porous titanium thick coating on titanium-based implants. The elastic modulus of the porous titanium coating can be matched with the host bone...

AI Technical Summary

Problems solved by technology

At present, the existing preparation methods of porous titanium coatings are: (1) stacking sintering method, such as stacking titanium balls, titanium short fibers, titanium mesh or TiH 2 Carry out sintering (U.S. Patent US4206516), but the porous coating prepared by this method has low bonding strength with the substrate, problems such as titanium balls or short fibers are easy to fall off; (2) thermal spraying method

In 1971, US patent US3605123 reported plasma spraying TiH 2 Porous titanium coatings were prepared, but the obtained coatings had poor pore uniformity and connectivity

In 1985, the US patent US4542539 prepared a porous titanium gradient coating by flame spraying, but the bonding strength of the coating was low, only 7MPa

The Japanese kobesteel company prepared a porous titanium coating by vacuum plasma spraying, with a porosity of 40-60%, an elastic modulus of 4.7GPa, and a compressive strength of 85MPa; Sulzer Calcitek successfully applied the porous titanium coating prepared by vacuum plasma spraying. It is used in dental implants, and obtained FDA certification in 1997 and entered the market; however, vacuum plasma spraying equipment is expensive, and ordinary companies cannot afford it. In addition, the porous titanium coating prepared by this technology has problems such as pore uniformity and poor connectivity of openings.

Chinese patent 99123708.0 reports a method of spraying "titanium-aluminum" mixed powder by flame or plasma, and then soaking in alkali solution to remove aluminum to prepare porous titanium coating, but the bonding strength of the coating is only 25-45MPa, and there is a process cycle Problems such as difficulty in preparing long and thick coatings