Relatively speaking, it is better to make metals and ceramics. Some chemicals will be used for metallographic preparation of metal materials. If you are engaged in the research of nano-ceramics in ceramics, it is said that nano-particles can directly penetrate human cells and enter the human body, which should be harmful. Then some tests, such as scanning electron microscopy, will have radiation hazards.
Extended data:
Materials are substances used by human beings to make machines, parts, devices and other products. But not all substances can be called materials, such as fuels and chemical raw materials, industrial chemicals, foods and medicines. Generally, it is not considered as material. Materials can be classified in many ways. According to physical and chemical properties, it can be divided into metal materials, inorganic nonmetallic materials, organic polymer materials and composite materials.
According to the use, it is divided into electronic materials, aerospace materials, building materials, energy materials, biological materials and so on. In practical application, it is often divided into structural materials and functional materials. Structural materials are based on mechanical properties and used to manufacture components with stress as the main force. Structural materials also require physical or chemical properties.
Such as gloss, thermal conductivity, radiation resistance, oxidation resistance and corrosion resistance. According to the different uses of materials, there are different requirements for performance. Functional materials are a kind of materials that mainly use the physical and chemical properties of substances or the different reactions of biological phenomena to external changes. Such as semiconductor materials, superconducting materials, photoelectric materials, magnetic materials, etc.
Baidu encyclopedia-material science