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D1649-01 – Standard Test Method Technical Guide
🧪 Composition and Chemical Requirements
This specification covers the pigment commercially known as strontium chromate, suitable for use in protective or decorative coatings. The pigment must be commercially pure strontium chromate free of extenders and organic matter, except for properties-enhancing additives. The dry pigment shall conform to the following chemical requirements:
| 🔬 Component | 🎯 Requirement |
|---|---|
| Strontium as SrO | Min 48% |
| Chromium as CrO3 | Min 47% |
| Chloride as Cl | Max 0.1% |
| Sulfate as SO3 | Max 0.2% |
| Water content | Max 0.2% |
| Coarse particles (No. 325 sieve) | Max 1.0% |
Additionally, the mass color and tinting strength must fall within agreed-upon limits when tested per Test Method D387.
📋 Test Methods and Sampling Procedures
All tests shall be conducted using standard ASTM methods. Chemical analysis follows Test Methods D1845, while water content is determined using Test Methods D1208. For color properties, Test Method D387 applies.
| 📏 Test Method | 🔍 Application |
|---|---|
| D1845 | Chemical analysis of strontium chromate |
| D1208 | Water content determination |
| D387 | Color and tinting strength evaluation |
Ensure that all testing equipment is calibrated and that samples are representative of the lot. Composite sampling can reduce variability.
Sampling shall include two random samples from different packages per lot. For shipments less than 10,000 lb, two samples are taken; for larger quantities, two samples per 10,000 lb. Samples may be tested individually or blended into a composite sample.
Chloride and sulfate levels must be strictly controlled to ensure corrosion inhibition properties.
❓ Frequently Asked Questions
🔍 What is the minimum strontium oxide content?
The minimum strontium oxide (SrO) content is 48% by weight.
💡 How is water content measured in strontium chromate?
Water content is determined using ASTM Test Methods D1208.
⚡ What are the maximum allowed impurities for chloride and sulfate?
Chloride (Cl) is limited to 0.1% maximum, and sulfate (SO3) to 0.2% maximum.
📌 What is the sampling procedure for strontium chromate pigment?
Two samples must be taken from different packages per lot. For large shipments, two samples per 10,000 lb are required.