The standards are designed to be "precise and quantitative, to give a particular number to tell what their adhesion or corrosion performance will be," said Duane Fudge, a chemical engineer with Betz Dearborn who prepared the draft standards with other members of ASTM Subcommittee D01.53 on Coil Coated Metal. Subcommittee members represent the steel, chemical and coatings industries.
Draft Standard Practice for Determination of Phosphate Coating Weight on Zinc-Coated Steel will calculate the weight of phosphate conversion coatings on hot-dip galvanized and electrogalvanized steel. An ammonium solution removes the phosphate, and weight loss is used to calculate coating weight.
Draft Standard Practice for Determination of Phosphate Coating Weight on Cold Rolled Steel will determine the weight of iron phosphate conversion coatings on cold rolled steel. A chromic acid solution removes the phosphate compounds, and weight loss is used to calculate coating weight.
Both standards address required reagents, preparation of stripping solution, apparatus, test specimens, procedure, and evaluation. More information is available from Duane Fudge, Betz Dearborn, 4636 Somerton Road, Trevose, PA 19053; phone 215/942.3276; fax 215/942.3311; e-mail duane.w.fudge@ BetzDearborn.com. More information on meetings of ASTM Committee D-1 on Paint and Related Coatings, Materials and Applications is available from Tim Brooke, ASTM, phone 610/832.9729; e-mail firstname.lastname@example.org.