Ti-Mg-B surface conditioner for zinc-phosphating and preparation method thereof

Abstract

The invention discloses a Ti-Mg-B surface conditioner with stable performance and long service life for zinc-phosphating and a preparation method thereof. The surface conditioner comprises the following raw materials by weight percent: 1-10% of titanium sulfate or titanyl sulfate, 10-50% of disodium hydrogen phosphate, 5-15% of sodium pyrophosphate, 5-15% of sodium bicarbonate, 1-10% of magnesiumsulfate, 1-10% of borax, 1-8% of trisodium phosphate and 0.1-1.5% of polycarboxylic acid anionic organic compound. The preparation method comprises the following steps: using a defined amount of disodium hydrogen phosphate to prepare an aqueous solution with the concentration of 50%, adding half of a defined amount of sodium pyrophosphate, and defined amounts of titanium sulfate or titanyl sulfate, sodium bicarbonate, borax, trisodium phosphate and polycarboxylic acid anionic organic compound in the aqueous solution of disodium hydrogen phosphate, heating to 70-80 DEG C, fully stirring to obtain white powder with the water content of less than 5%, continuously stirring the powder at 80-100 DEG C while adding the residual sodium pyrophosphate and a defined amount of magnesium sulfate, and continuously stirring and drying to obtain powder with the water content of less than 2%.

Description

technical field [0001] The invention relates to a surface regulator for phosphating and a manufacturing method thereof, in particular to a Ti-Mg-B surface regulator for zinc-based phosphating with stable performance and long service life. Background technique [0002] Iron and steel workpieces generally need to be degreased with strong alkaline working fluid or derusted with acidic working fluid before phosphating treatment. For this reason, the surface of steel workpieces will be corroded by acid and alkali, so that the workpiece will easily form coarse crystals in the phosphating treatment process. The phosphating film layer has poor corrosion resistance. In order to change the surface state of iron and steel workpieces, accelerate the phosphating process, reduce the phosphating temperature, and promote the formation of fine and dense phosphating film layers, surface adjustment agents are usually used for surface adjustment before phosphating treatment. At present, there ...

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Problems solved by technology

Although the Ti-based surface conditioner has a very ideal surface adjustment effect, its disadvantage is that it is easy to age (the service life can only be maintained for 3 to 4 days), and its surface is very easy to form blue oxide scale or purple oxide scale, resulting in The surface of the treated workpiece cannot form a normal phosphating film (the phosphating film has coarse crystals, the film thickness increases by more than 25-50%, and even produces yellow spots); the Ti-Mg series surface regulator contains pyrophosphate, and its function is to prevent colloid Ti Ning

But P 2 o 7 -4 It will also react with the steel surface to form an inactive passivation film; Mg ++ Although it is possible to prevent P 2 o 7 -4 Passivation of steel, but due to Mg / P 2 o 7 The ratio control in the process is very strict, and the inhomogeneity of the process consumption often leads to a sharp drop in the surface adjustment effect, and uneven blue or white films will be produced on the metal surface after phosphating; The problems directly affect the normal operation of the phosphating production line