Because porous materials have an open, porous structure that allows for the traditional growth of new bone cell tissue and body fluids, and because porous materials have young's modulus that adjusts the porosity to match natural bone, improving its biomechanical compatibility.Porous titanium with excellent biocompatibility and good corrosion resistance has attracted wide attention in the medical community.At present, the preparation methods include the following categories:
1. Solid sintering method
The methods mainly include metal stacking sintering method, adding pore-making agent method, paste foaming sintering method, template method, combustion synthesis method and so on.
1) metal deposit sintering method is a method that the accumulated hollow balls or powders are sintered at high temperature to form metallurgical combination to prepare porous metals through high temperature diffusion.In addition, the metal wire winding method can also be used to form billet and resintering to prepare porous materials.
2) this method is to mix the pore-making agent and titanium powder evenly in a certain proportion, and then remove the pore-making agent before or after sintering by heating or dissolving, so as to obtain the porous structure.The method is applicable to a wide range of applications, the preparation process is simple, and the pore distribution is uniform.
3) paste foaming method is based on metal powder as raw material. By adding foaming agent and other mixing paste, and then adding into the mold for heating, the gas generated by the effect of additives and foaming agent begins to expand. After sintering, porous metal can be obtained.
4) the template method can also be used to prepare porous titanium, which generally takes sponge as the template, impregnates the titanium slurry in the template, and then heats the template after drying, and finally obtains porous titanium and its alloy through high temperature sintering.
2. Liquid solidification method
According to different heating sources, it can be divided into electron beam heating forming method and laser engineering net forming method.
1) electron beam processing
Electron beam processing is a special processing method that makes use of the heat energy generated when the electron beam with high power density hits the workpiece to melt and vaporize the material.This method is also one of the common methods in the rapid prototyping technology.
2) laser engineering net forming method
The laser engineering net shaping method is also a kind of rapid prototyping technology, the technology with the aid of computer aided design, using the rapid prototyping processing technology after the three-dimensional entity model into plane information generating nc code, and finally to the control center and accumulated the massive base for laser heating melting raw materials and preparation of the solid parts.
3. Metal deposition method
Metal deposition mainly includes vacuum evaporation, electrodeposition, plasma spraying and reaction deposition, among which the most common deposition method is plasma spraying.In general, plasma spraying has unique advantages in preparing thin films or coatings, and the method can also be used to process porous metals.