This trivalent chromium passivation process which without hexachromium and oxidizer, it passed SGS
the range of operation to assure normal operation of passivation. 3. in the use of passivation bath, must check PH value and temperature of the passivation solution, they should be in 250-300ppm). the iron impurity can easily get into passivation solution to effect passivation solution.(max capacity of iron is 2. bath, heating or cooling equipment or tool basket do not use the ironed or stainless steel equipment, in this way zinc is 10g/l). also speed up, and it can overcome the phenomena of quick reaction through shortening time.(max capacity of 1. passivation is carrying on though, the content of zinc in the bath will increase, so the velocity of passivation will Note: 250ppm) If without effects by changing 1 and 2, still appearing yellow color, it is iron impurity problem (iron is more than increasing the concentration of passivation solution(ideality concentration is 7vol%) extending the time of passivation adjusting PH with diluted solution of sodium bicarbonate 3. 2. 1. extending the time of passivation adjusting to the range of the process greater than 1.7 Short time Concentration too low PH too low 6. Passivation insufficient ------- red yellow Reducing passivation time. Adjusting the concentration of passivation solution to the range of the process. Adjusting pH to the range of process with diluted nitric acid. 3. 2. 1. confirm with practical needs of parts not greater than 7vol% generally should be less than 2.2 Time too long Concentration too high PH too high 5. Excessive passivation ------- yellow (yellow) (red-yellow) (yellow) possibility appearing in color Iron impurity Passivation insufficient Excessive passivation Cause 3. 2. 1. Bring about yellowing problem: 4. How to use TR-121 correctly metal impurity. dragged in for treatment uncompleted zinc plating parts (long tubes),TR-121 is sensitive to lead and other heavy iron ions, according to concentration of built bath, the range of iron ions is 250-500ppm,plenty of iron ions can be parts in alkaline zinc plating. The TR-121 without use time limitation, the effective factor is the concentrations of Serving as last step process before passivation, we recommend an acid dip by 0.5%Vol nitric acid, especially for Hint: practice operation. condense solution of TR-121,about 12000-14000dm2/l, the customer can adjust additive quantity according to According to normal operation, do not consider drag-out and drag-in of solution, only due to passivation consume Consume: Workpiece movement or air agitation Agitation: The steel bath with resistance acid plastic lining appear yellow color on the surface of passivation reduce resistance erosion power adjusting with nitric acid or sodium bicarbonate (or sodium carbonate) 2.0 25°C 20-30sec 7 Vol% best operation 1.7-2.2 15-30°C remove irons water 10-20 sec 5-12Vol% range of operation Material of bath: PH>2.2 PH<1.7 PH Temperature: Water nine(before dry) Immersing time: TR-121 (condense solution) Make-up of new solution good strength. The 3. Operation conduction: nine ? hot water nines(remove irons water) ? water zinc plating ? nine ? immersed HNO3(0.5%) ? nine ? immersed TR-121 ? cold water 2. Process flow: F. According with American GME 0025 and GMW-3044 standard. E. The using time is longer, it is more effective to use latter nine bath solution. environment requirement. D. Because it is trivalent chromium solution, it reduces the cost of waste water treatment, also can satisfy for passivation layer is easy to dye by organic dye. C. Even through short immerging time, it can form blue-white passivation layer with erosion standard. B. The blue-white passivation workpiece for barrel plating is also apparently superior to general resistance international accreditation A. This trivalent chromium passivation process which without hexachromium and oxidizer, it passed SGS 1. Character:
TR-121 trivalent chromium blue-white Passivator
