| Mineral Type |
Muscovite or phlogopite mica, depending on the required electrical, thermal and optical properties. |
Muscovite generally offers good electrical insulation and light color, while phlogopite usually provides better heat resistance and a darker appearance. |
Review the mineral identification report, X-ray diffraction result or equivalent technical documentation. |
Specify the mica type before requesting quotations; mineral type can affect color, dielectric performance and heat resistance. |
| Particle-Size Distribution |
Common powder grades include approximately 200 mesh, 325 mesh and fine grades below 20 micrometres. The required D50 and maximum particle size should be stated separately. |
Particle size influences surface finish, dispersion, viscosity, sedimentation and the appearance of cured epoxy coatings or castings. |
Request laser particle-size analysis or sieve analysis showing D10, D50, D90 and residue on the selected sieve. |
Do not rely on mesh size alone. Ask for the complete particle-size distribution and batch-to-batch tolerance. |
| Color and Whiteness |
White, off-white, silver, golden or brownish mica may be available, depending on the mineral source and processing method. |
Color affects decorative coatings, pearlescent effects, electrical insulation appearance and the final shade of transparent or pigmented epoxy. |
Compare a sealed reference sample under consistent lighting and request a whiteness or color test where applicable. |
Define an approved color standard and acceptable color difference before mass purchasing. |
| Moisture Content |
Dry mineral powder is normally preferred; a common internal purchasing target is no more than about 0.5% moisture, subject to the formulation. |
Excess moisture can increase bubbles, reduce wetting, affect curing behavior and impair electrical insulation performance. |
Use a moisture analyzer or oven-drying method and verify the result on several production lots. |
Require moisture control during drying, packing and storage. Resealable moisture-resistant packaging is beneficial. |
| Oil Absorption |
Often reported in grams of linseed oil absorbed per 100 g of powder; the acceptable range depends on particle size and surface area. |
Higher oil absorption can increase epoxy viscosity and resin consumption while influencing loading level and flow. |
Request the supplier's oil-absorption test method and compare results using the same laboratory procedure. |
Use the measured value to calculate resin demand rather than selecting solely by price per kilogram. |
| Epoxy Dispersion |
The powder should wet and disperse uniformly in the selected epoxy system without visible agglomerates under the intended mixing conditions. |
Poor dispersion may create weak areas, surface defects, uneven color and inconsistent dielectric properties. |
Conduct a laboratory let-down test using the actual resin, hardener, mixing speed and loading level. |
Request a sample before approving the supplier. A compatible grade may reduce mixing time and reject rates. |
| Thermal Stability |
Mica is an inorganic mineral with strong heat resistance; the practical limit is determined by the mica type, coating treatment and epoxy system. |
Thermal stability is important for electrical insulation, heat-resistant coatings, potting compounds and industrial composites. |
Review thermal analysis data and perform a heat-aging test on the complete epoxy formulation. |
Evaluate the finished compound rather than the mineral powder alone, because epoxy degradation may occur before mica degradation. |
| Electrical Insulation |
High-quality mica is commonly selected for dielectric and insulating applications, but performance depends on purity, moisture, orientation and resin formulation. |
Electrical properties affect insulation reliability, breakdown strength and long-term performance in electrical components. |
Request volume resistivity, dielectric strength or dielectric-loss data where relevant, and test the finished compound. |
Specify the test standard, specimen preparation and conditioning requirements to make supplier data comparable. |
| Purity and Foreign Matter |
Low levels of quartz, feldspar, iron-bearing minerals, grit and other non-mica particles are preferred for high-performance epoxy applications. |
Foreign matter can increase abrasion, darken the product, reduce insulation reliability and cause processing defects. |
Review X-ray diffraction, microscopy, chemical analysis and residue-on-sieve results. |
Set limits for visible impurities, coarse particles and magnetic or metallic contamination where necessary. |
| Heavy-Metal and Regulatory Compliance |
Compliance should be confirmed for the intended market and application, including restrictions on lead, cadmium, mercury and hexavalent chromium when applicable. |
Regulatory non-compliance can delay customs clearance, restrict market access and create product-liability risks. |
Request a recent third-party test report and a signed material declaration covering the destination market. |
Check requirements under the applicable chemical, environmental, packaging and product-safety regulations before ordering. |
| Surface Treatment |
Untreated mica is common, while silane or other surface treatments may be considered for improved resin wetting and interfacial bonding. |
Surface treatment can influence adhesion, moisture resistance, dispersion and mechanical performance. |
Ask for treatment chemistry, treatment level and comparative resin-compatibility data. |
Confirm that the treatment is compatible with the epoxy resin, curing agent and service temperature. |
| Packaging |
Common industrial packaging includes moisture-resistant bags, woven bags with inner liners or sealed multiwall paper bags; larger quantities may use big bags. |
Improper packaging can cause moisture pickup, contamination, caking and weight discrepancies during transportation. |
Inspect packaging specifications, net weight, palletization and seal integrity on the pre-shipment sample. |
State the required bag size, labeling, pallet condition and protection against water during ocean transport. |
| Batch Consistency |
Particle size, moisture, color, purity and oil absorption should remain within agreed specifications from lot to lot. |
Consistent raw material reduces formulation adjustment, production downtime and finished-product variation. |
Compare certificates of analysis from multiple lots and retain an approved reference sample. |
Include specification tolerances, inspection rights and corrective-action procedures in the purchase agreement. |
| Sampling and Trial Approval |
A representative pre-production sample should be tested in the buyer's actual epoxy formulation before commercial approval. |
Laboratory data alone may not predict dispersion, viscosity, surface appearance or curing performance in the final formulation. |
Run a controlled trial with fixed resin ratio, loading, mixing procedure, cure schedule and performance tests. |
Approve the grade only after the sample meets both processing and finished-product requirements. |
| Technical Documentation |
Important documents include a technical data sheet, safety data sheet, certificate of analysis, specification sheet and country-of-origin information. |
Complete documentation supports quality control, worker safety, customs procedures and regulatory review. |
Check document dates, test methods, batch numbers and consistency between the documents and the physical sample. |
Make document submission a condition of purchase and require notification before any material or process change. |
| Lead Time and Supply Capacity |
Lead time depends on grade, production schedule, packaging and export arrangements; it should be confirmed for both trial and repeat orders. |
Reliable delivery protects production planning and reduces the risk of emergency substitutions. |
Review historical delivery performance, production capacity and contingency arrangements. |
Compare total supply reliability rather than selecting only the lowest quoted unit price. |
| Total Delivered Cost |
Evaluate product price together with packaging, inland transport, freight, insurance, duties, inspection and potential formulation adjustments. |
A lower purchase price may be offset by higher moisture, poor dispersion, greater resin consumption or increased rejection. |
Prepare a landed-cost model using the same Incoterm, quantity, destination and quality requirements. |
Use cost per accepted kilogram or cost per finished part as a more meaningful comparison than price per kilogram alone. |
