1.Raw materials and instruments
1.1 Raw materials
White corundum [M (Al2O3) ≥ 99%], attapulgite, CMC (sodium carboxymethyl cellulose), PVA (polyvinyl alcohol), efka 3288, zinc oxide, sodium pentachlorophenol, silicone defoamer and other additives are all industrial grade.
Zmd-550 dispersion sand mill, tu-4 cup, NDJ-5S rotary viscometer, gas evolution tester, casting coating wear resistance tester, sintering point tester, etc.
2.Preparation of casting coating
The pretreated attapulgite slurry was prepared by mixing attapulgite with water at the mass ratio of 1 ∶ 4 and completely dispersing evenly.
Add sufficient water into the dispersion tank, slowly add CMC under the state of high-speed stirring, then raise the temperature to 60 ℃, and continue stirring for 30 min to completely dissolve it.
Add sufficient water into the dispersion tank, slowly add PVA under the state of high-speed stirring, then raise the temperature to 80 ℃, and continue stirring for 20 min to completely dissolve it.
Add water, sodium pentachlorophenol, organosilicon defoamer and pretreated attapulgite slurry into the dispersion tank and disperse at a high speed of 1200 R / min for 20 min; CMC pretreatment solution and PVA pretreatment solution were added successively and dispersed for 20 min; Add other additives, then add white corundum in batches, continue to disperse for 20 minutes, and the preparation is completed.
3.Performance analysis of casting coating
3.1 Determination of wear resistance of coating
Refer to the mechanical industry standard JB / T 9226-2008 casting coatings, and use the casting coating wear resistance tester to determine the wear resistance strength of the coating.
3.2 Determination of shear dilution index of casting coatings
NDJ-5S rotary viscometer was used to measure the viscosity of casting coatings at 6 R / min and 60 R / min shear rates respectively. The ratio of the two is the shear dilution index of casting coatings, which reflects the shear thinning characteristics of casting coatings.
3.3 Determination of burning point of refractory aggregate
The burning point of refractory aggregate is measured by burning point tester.