Biomedical metal materials refer to alloys or metal materials used in medical treatment. Because of their high fatigue resistance and mechanical strength, they are widely used in surgical aids, artificial organs, hard tissues, and soft tissues. In clinical medicine, cobalt-based alloys, titanium-based alloys, stainless steel, shape memory alloys, precious metals, pure metals such as niobium, zirconium, titanium, and tantalum are widely used due to their properties. In recent years, with the innovation of raw materials and technological development, coupled with the special use scenarios of medical materials, higher requirements have been put forward for the safety and biocompatibility of related materials. Although new types of biometal materials such as powder metallurgy alloys, high-entropy alloys, and amorphous alloys continue to emerge, their clinical use is limited. Therefore, it is particularly important to increase research on medical metal materials.
01 Biomedical titanium alloy materials
Titanium and titanium alloy materials have more suitable biomedical properties due to their low elastic modulus, high specific strength, excellent biocompatibility and corrosion resistance, and are widely used in artificial joints (hip, knee, shoulder, Ankles, elbows, wrists, finger joints, etc.), bone trauma products (intramedullary nails, fixation plates, screws, etc.), spinal orthopedic internal fixation systems, dental implants, dental trays, orthodontic wires, artificial heart valves, interventional hearts Vascular stents, etc.
02 Cobalt-based alloy medical metal materials
Medical cobalt-based alloys generally contain cobalt, chromium, nickel, molybdenum, tungsten and other elements. Chromium can form a dense oxide layer on the surface of the alloy, which can improve the corrosion resistance of the alloy. Chromium can also form carbides, which have higher Hardness can increase the strength of the matrix and at the same time increase the wear resistance of the alloy. The molybdenum element in the alloy is solid-dissolved in the matrix and can become a barrier to the flow of dislocations, thereby increasing the strength of the matrix. Therefore, the medical cobalt-based alloy has superior performance, excellent mechanical, abrasion resistance, corrosion resistance, and biocompatibility. It is widely used in the biomedical field as artificial joints, dentures, stents, etc.
03 Stainless steel medical metal material
Medical stainless steel has the advantages of low price and easy processing. It can be made into various artificial prostheses and various shapes, such as crowns, triangular nails, screws, and pulp
Internal needles, plates, nails and other devices are widely used in stomatology, fracture internal fixation devices, artificial joints and other fields. At the same time, it is widely used in the production of surgical instruments and medical instruments. At this stage, it is the most widely used medical metal material.
04 Biomedical aluminum alloy materials
Aluminum and its alloy materials have been widely used as implant materials in medical treatment as early as the 1940s because of their good plasticity and biocompatibility.
Secondly, aluminum has high corrosion resistance. Except for dissolving in a mixture of hydrofluoric acid, caustic alkali, hot concentrated sulfuric acid, hydrochloric acid and nitric acid, aluminum has stable performance under the action of other reagents, and the alternating fatigue strength has little effect. , The good biocompatibility makes the aluminum implant material have little rejection with the human body. In addition, compared to stainless steel, aluminum has a high resistance to notch crack propagation.
05 Biomedical zirconium alloy materials
Zr is a metal with excellent corrosion resistance, good tissue compatibility, and non-toxicity. It is often used as an alloying element to be added to Ti alloys to improve the mechanical properties of Ti alloys. In recent years, new biomedical alloy materials have been developed by adding non-toxic and side-effect alloy elements to strengthen and optimize Zr alloys. Zr-based biomedical alloy materials have gradually attracted people’s attention due to their low elastic modulus, high strength, good corrosion resistance in physiological environments, and good biocompatibility. They are used as a substitute for human hard tissue and are widely used in medical treatment. field.
06 Biomedical biodegradable magnesium alloy materials
Magnesium alloy has good biocompatibility and degradability. Porous magnesium alloy material has the dual advantages of porous metal and magnesium alloy. As a biodegradable material, it can provide three-dimensional growth space for cells, which is beneficial to nourishment and metabolism. Exchange and transportation of goods. Magnesium itself has biological activity and can induce cell differentiation and growth and blood vessel growth. In the process of material degradation and absorption, the planted cells will continue to proliferate and grow, and it is expected to form new corresponding tissues and organs with the original specific functions and shapes to achieve the purpose of repairing wounds and rebuilding functions. The complete degradability and outstanding biocompatibility of biomedical biodegradable magnesium alloy materials make it expected to be widely used in clinical hard tissue repair or replacement. Degradable magnesium alloy vascular stent is the largest research progress in the field of magnesium alloy as a biodegradable biomedical metal material.
07 Biomedical degradable zinc-based alloy materials
Biomedical zinc alloy is a new type of biomedical biodegradable metal material. Although the mechanical properties of zinc are insufficient in applications, alloying can overcome its defects and improve its biological properties: the addition of magnesium can increase the cell phase of zinc. Capacitiveness, copper and silver can enhance the antibacterial properties of the alloy, and the addition of zirconium can improve the mechanical properties and corrosion resistance of zinc alloys. More zinc-based alloys are in the research stage. As a new generation of degradable metals, zinc alloys have broad Application prospects.
08 Other biomedical metal materials
(1) Tungsten: Tungsten is the element with the highest melting point except carbon. Due to its good radiopacity and thrombosis, pure tungsten mechanically detachable microcoils are used in interventional surgery to treat cerebral aneurysms. It also shows good biocompatibility, but the degradability of tungsten often leads to recanalization of blocked blood vessels and an increase in the concentration of tungsten ions in the serum.
(2) Precious metal materials: Medical precious metal materials refer to gold, silver, platinum and their alloys. Precious metals are expensive but have good biocompatibility and ductility. They are one of the earliest medical metal materials used by humans.
(3) Bulk amorphous alloys: bulk amorphous alloys have the characteristics of high strength, high hardness, high wear and corrosion resistance, high fatigue resistance, and low elastic modulus. They are based on titanium, zirconium, iron, and magnesium. Mainly based on calcium and calcium, which can be used for bone plates, screws, pacemakers, etc.
(4) High-entropy alloys: High-entropy alloys are generally alloyed with more than 5 elements in atomic ratio or close to equal atomic ratio, and their mixing entropy is higher than the melting entropy of the alloy. High-entropy alloys have some excellent properties that traditional alloys cannot match, such as high strength, high hardness, high wear and corrosion resistance, low elastic modulus, and good biocompatibility. In addition, by adding different elements, such as silver, copper, etc., it can also have antibacterial properties.