Борид хрома (Cr2B)

Identification

Chromium boride (Cr2B), dichrome boride, is a binary inorganic compound of chromium and boron with a composition of 2:1 from the group of transition metal borides. CAS number 12006-80-3, chemical formula BCr2.

Basic Attributes

• CAS No.: 12006-80-3
• Chemical formula: BCr2
• Molecular Weight: 62.8071
• Exact weight: 65.97330
• EU number: 234-488-3
• PSA: 0

Substance class and structure

Cr2B belongs to the chromium boride family, along with CrB and CrB2, and crystallizes in a tetragonal structure such as CuAl2, where the boron atoms are isolated from each other and surrounded by chromium atoms. This structure distinguishes Cr2B from CrB2 and CrB, where boron atoms form networks or chains, and defines it as the most metal-like of the three phases of the chromium-boron system. Like related borides, Cr2B is produced by reducing chromium oxide with boron or boron carbide at high temperature, followed by grinding into powder and, if necessary, sintering into dense products.

Scope of application

Like other chromium borides, Cr2B is used in powder metallurgy and the production of wear-resistant and heat-resistant coatings applied by spraying to metal and ceramic surfaces. The compound is used as a strengthening phase in composite materials and hard alloys, as well as in protective layers of parts operating at elevated temperatures and under conditions of abrasive wear. The increased content of metallic chromium compared to CrB and CrB2 provides Cr2B with higher ductility while maintaining the hardness characteristic of borides, which is in demand in compositions where both wear resistance and cracking resistance are important.

Storage and handling

Store in an airtight container in a dry place, away from moisture. When working with powder, avoid dust and use respiratory and eye protection. Waste and powder spills are removed dryly and disposed of in closed containers, preventing them from entering drains.

Place of Cr2B among chromium borides

In the chromium-boron system, Cr2B is the phase richest in metal (ratio of chromium to boron 2:1), in contrast to CrB (1:1) and CrB2 (1:2). The higher chromium content gives Cr2B intermediate mechanical properties between pure metal and brittle borides with a higher proportion of boron: the compound retains metallic ductility to a greater extent than CrB and CrB2, which is important for parts operating under cyclic mechanical loads.

Additional data

There is no separate information on the toxicity and danger of Cr2B in open sources; When working with powder, apply the general precautions taken for refractory inorganic borides of transition metals - avoid dust, exhaust ventilation, personal protective equipment for the respiratory system and skin.

Delivery forms

The compound is supplied in powder form under the designation dichrome boride or Cr2B, and is packaged in sealed containers to prevent contact with atmospheric moisture during storage and transportation.