초록

Alkyl-substituted hydroxylamines are useful as aids in the phosphating of metal substrates. In particular, the rate of phosphating and the rate at which manganese compounds are dissolved into aqueous phosphoric acid solutions may be accelerated by alkyl-substituted hydroxylamines.

대표청구항 ▼

What is claimed is: 1. A phosphate conversion coating composition which is acidic and which is comprised of: a) water; b) cations selected from zinc cations, alkali metal cations, ammonium cations or mixtures thereof; c) phosphate ions; and d) a water-soluble substituted hydroxylamine corresponding

What is claimed is: 1. A phosphate conversion coating composition which is acidic and which is comprised of: a) water; b) cations selected from zinc cations, alkali metal cations, ammonium cations or mixtures thereof; c) phosphate ions; and d) a water-soluble substituted hydroxylamine corresponding to general formula wherein R1, R2 and R3 are the same or different and are independently selected from H and C1-C6 alkyl, subject to the proviso that R1, R2 and R3 are not all H, or a salt of said water-soluble substituted hydroxylamine; said phosphate conversion coating composition having a total acid content of from about 10 points to about 100 points. 2. The phosphate conversion coating composition of claim 1 comprising zinc cations. 3. The phosphate conversion coating composition of claim 1 additionally comprising at least one stabilizer containing at least one moiety selected from--C(O)NH2 or--S(O)2NH2 per molecule. 4. The zinc phosphate conversion coating composition of claim 3 wherein the stabilizer is present in an amount such that the mole ratio of stabilizer to substituted hydroxylamine is from about 0.05:1 to about 1.2:1. 5. The phosphate conversion coating composition of claim 1 wherein at least one of R1 or R2 is C1-C6 alkyl. 6. The phosphate conversion coating composition of claim 1 wherein R1 and R2 are the same or different and are both C1-C6 alkyl and R3 is H. 7. The phosphate conversion coating composition of claim 1 wherein R1 and R2 are ethyl and R3 is H. 8. The phosphate conversion coating composition of claim 1 wherein R1 and R3 are H and R2 is isopropyl. 9. The phosphate conversion coating composition of claim 1 wherein said water-soluble substituted hydroxylamine is present at a concentration of about 1 to about 200 mmoles/L. 10. A zinc phosphate conversion coating composition which is acidic and which comprises: a). water; b). zinc cations; c). phosphate ions; and d). 1 to 200 mmoles/L of a substituted hydroxylamine selected from N-isopropyl hydroxylamine, N,N-diethyl hydroxylamine, salts thereof or mixtures thereof. 11. The zinc phosphate conversion coating composition of claim 10 comprising 0.05 to 7.5 weight % zinc cations, 0.5 to 8.0 weight % phosphate ions, and 1 to 200 mmoles/L substituted hydroxylamine selected from N-isopropyl hydroxylamine, N,N-diethyl hydroxylamine, salts thereof or mixtures thereof. 12. The zinc phosphate conversion coating composition of claim 10 additionally comprising sulfamic acid. 13. The zinc phosphate conversion coating composition of claim 12 wherein the sulfamic acid is present in en amount such that the mole ratio of sulfamic acid to substituted hydroxylamine is from about 0.05:1 to about 1.2:1. 14. The zinc phosphate conversion coating composition of claim 10 additionally comprising nickel cations. 15. The zinc phosphate conversion coating composition of claim 10 additionally comprising nitrate anions. 16. A zinc phosphate conversion coating composition having a pH of 1 to 2 and comprising: a). water; b). 1.8 to 2.2 weight % zinc cations; c). 2.7 to 3.3 weight % phosphate ions; d). 0.02 to 0.05 weight % N,N-diethyl hydroxylamine or salt thereof; e). 50 to 70 ppm Ni: f). 3.2-3.8 weight % nitrate; and g). 0.015 to 0.025 weight % sulfamic acid. 17. A phosphate conversion coating composition comprising: a) water; b) cations selected from zinc cations, alkali metal cations, ammonium cations or mixtures thereof; c) phosphate ions; and d) a water-soluble substituted hydroxylamine corresponding to general formula wherein R1, R2 and R3 the same or different and are independently selected from H and C1-C6 alkyl, subject to the proviso that R1, R2 and R3 not all H, or a salt of said water-soluble substituted hydroxylamine; e) optionally, fluoride ions and/or nitrate ions; f) optionally, additional metal ions selected from nickel ions, cobalt ions, calcium ions, magnesium ions, manganese ions, iron ions and mixtures thereof. 18. The phosphate conversion coating composition of claim 17 comprising 1 to 200 mmoles/L water-soluble substituted hydroxylamine selected from N-isopropyl hydroxylamine, N,N-diethyl hydroxylamine, salts thereof or mixtures thereof.