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A layer of thick or thicker SHELL not difficult to achieve
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Boron nitride coating for ferrous metal casting has been used for many years. As we all know, BN has the performance of the larger contact angle θ in the range of metal melting temperature, thus it is particular outstanding for aluminum, magnesium, zinc, copper and their alloys of nonwetting property. These coatings have the characteristic of exhibiting nonwetting/non-stick properties with these molten metals and their drosses/slags.
An ideal coating not only has the property of Non-Stick，but also should be non-reaction and hot-shock and washing resistion |
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Generally,the common BN coatings have the property of non-stick，but could hardly have the non-response and hot-shock resistion with molten metals.
This relates to the components of additives added. these coatings are therefore typically thiner .This characteristic results in eventual wear and erosion by molten metal moving across the coated surfaces so as to eventually be consumed, aeroded by molten metal moving,crack easy and shorter life.
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Mud-Cracking |
Only possible solution to the erosion problem would be to provide a thicker boron nitride coating. Unfortunately, thick coatings require thorough drying between applications or else moisture is retained in the undercoatings.
Such residual moisture often leads to delamination or “pop-off” of the coatings when used for the first time. Thick coatings are also more susceptible to “mud-cracking” on drying which leads to the coating coming off of the substrate in poorly-attached areas. Another problem with thick boron nitride coatings arises from the thermal expansion differences between the substrate and the coating. Stresses arising from these thermal expansion differences become more pronounced with thicker coatings as they go through temperature changes, leading to spalling of the thick coatings. Thick coatings typically have less strength than thin coatings due to microcracking and low cohesive bonding. Additionally, applying a thick coating is time-consuming for the process worker
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Disjunctum |
According to the latest technology, researched with the professional institutions of Chemical and Physics, a thick layer of boron nitride coating could be innovate or manufactured,such desire which thick layer coating used in non-ferrous metals casting could be easily achieved.
By brushing and drying frequently, matchs with the using of additives A or B, the coating thickness can reach 5mm accompany with high-strength, non cracks and non-reaction with the molten metal.
This “shell” coated on refractory ceramic surface results with a long-lasting boron nitride layer, such that recoating is unnecessary for periods of time up to several months as compared to days or even hours with standard boron nitride coatings. |
Delamination or pop-off |
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Blue |
Cambridge blue or White |
Advantage:
1. Non-reaction with the molten metal, smaller free energy of additives, replacement reaction with molten metal would not happen, which is the key factor of service life longer .
2. Thick and thicker coatings can be achieved.It ideally resolves the pop-off” from moisture or microcracking or thermal expansion differences with the substrate, No-mud-cracking. Coating thickness can reach 5mm. The surface still is smooth after polishing slightly,an erosion-resistant nonwetting layer would occur on the surface.
The same also applies to the substrates of metals
3. Super-fine compositions, larger surface area , stronger adhesion.
4. Choose among of components A or B,it will be more suitable for drying and preheating substrate.
5. Water-base coating, treat easily.
6. Brushing, rolling, dipping, spraying any process can be applied
7. Harmful ingredients free, safety and environmental protection
Applications:
1. Applied to ceramic substrate
Coated on the workpieces which contact with high-temperature liquid such as aluminum, magnesium, zinc casting, to prevent the substrate reacted, corroded, and heat shock resistance ,to prevent the corundum phase brought into, thereby reducing the slags, improving the flow rate of the metal.
◇Launder, ladle, skimmer, control pin, spout,, hot top rings and transition rings.
◇Degasser and filter units,distributor,translation boards, nozzle, casting platform
◇Float, casting tip, rotor,, thermocouple protection tube.
◇Heater protective tube, the crucibles, evaporation boats, and other porous ceramics and graphite matrix
2. Applied to metal substrate
◇To prevent reacting and corroding with high temperature metal, facilitate the mold releasing and lubrication
◇A variety of casting or founding models, extrusion models
◇Press and forging model and powder metallurgy
◇Model releaseing of ceramics and glass industry |
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A Company |
Ours |
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A Company |
B Company |
Ours |
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Products types:
A: BN White®
B: BN Blue®
C: BN White shell-094®
D: BN Blue shell-094®
Download，for
more PDF |
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Performance Index |
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Active components |
NB |
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Maximum service Temperature C° |
1000C°in the atmosphere |
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1400C°in a vacuum |
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1800C°in
an inert environment |
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Service environment |
Atmosphere |
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Diluent |
Water |
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Degree of viscosity |
900-1200 3/60 |
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Density |
1.12g/cm3 |
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Colour |
White, blue or special needs |
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Date of minimum durability |
>12 months |
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Application |
All substrates (especially ceramics, graphite, metal) |
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Packing |
in plastic drums, 4 drums into a cardboard case |
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Specifications |
5L drum, 5 kg each |
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