Not all metallographic samples need to be inlaid(also known as inlay sample),only in the sample size is too small or the shape is irregular,resulting in grinding and polishing difficulties,only need to be inlaid or clamped,which can make the sample easy to grind,improve the work efficiency and the accuracy of the experiment.In general,the following mosaic samples are required:
1:Small mechanical parts,such as complex shapes and very small samples,or small electronic components.
2:Protect the tissue and depth determination of the surface of the workpiece.
3:Samples for the determination of surface infiltration coating,coating tissue and depth.
Mosaic is divided into cold set and hot set,mechanical holding three kinds.
Hot setting:suitable for low temperature and low pressure.
Hot inlaid material:at present,plastic is generally used as inlaid material.Insaic materials include thermocoagulation plastic(such as rubber powder),thermoplastic(such as polyvinyl chloride),condensing plastic(epoxy resin plus curing agent)and medical dental powder plus water,etc.Plywood powder is not transparent,has a variety of colors,and relatively hard,the sample is not easy to chamferate,but the resistance to strong acid and alkali corrosion resistance is relatively poor.Polyvinyl chloride is translucent or transparent,acid and alkali corrosion resistance,but soft.
The above two materials need to be heated by a special inset heater.
Cold set:materials extremely sensitive to temperature and pressure,and samples with microcracks shall be cold set and will not cause changes in the sample tissue.Cold inlay can be used for large-scale simple sample inlay,short curing time,low shrinkage rate,strong adhesion;good corner protection,good wear resistance.Suitable for microelectronics industry;vacuum dipping of brittle materials,etc.
Cold inset material:generally include:epoxy resin,acrylic acid,polyester resin.
Epoxy resin:low shrinkage rate,long curing time;good edge protection,used for vacuum impregnation,suitable for porous materials.
Acrylic resin:yellow or white,short curing time,suitable for large quantities of irregular shape samples;good permeability for samples with cracks or pores;especially for printed circuit board packaging.
Polyester resin:yellow,transparent,long curing time;suitable for large quantities of samples without pores;long application period.