comparative hardness values

Vickers - HV 1   Brinell - HB 2   Rockwell - HRC 3  
320 304 32,2
340 323 34,4
360 342 36,6
380 361 38,8
400 380 40,8
430 409 43,6
460 437 46,1
490 - 48,4
500 - 49,1
550 - 52,5
600 - 55,2
650 - 57,8
700 - 60,4
800 - 65,7
900 - 70,9
1000 - 76,3

1 =  for hard and soft materials

2 =  for all   materialswhich are softer than hardened steel  

1 =  for hard materials, e.g. hardened steel                                        

 

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Electroless nickel - hardness of deposited layers

4 kinds of the hardness exist:

Vickers (HV), Rockwell (HRC), Brinell (HB), Knoop (HK)

      

Particularly to the determination of the hardness of Ni-P-layers the Vickers hardness is very common and most extensive in application.

Measurement principle: A diamond pyramid penetrates under defined conditions into the coat. The mathematical evaluation is made by the penetration depth of the pyramid diagonals. For avoidance of wrong measurements the minimum layer thickness must amount to approx. 20 Ám since the penetration depth of the pyramid needs up to 15Áms. Thinner layers are measured either in transverse cross section by 90░ or but based on an accompanying inspection piece parallel in a en bath.      

En layers are in the freshly deposited condition 3 time harder as galvanically deposited nickel layers - approx. 500 HV to 150 HV.

By differentiated heat treatments - partial under inert gas - and in dependence of the phosphorus content in the layer can be achieved hardness increases up to 1200 HV. 

Under adherence to consistent working conditions one obtains positive results in this connection to friction and wear protection rates, which are recognizable in principle over abrasion test.

 

 

 

 

 

 

 

 

 

 

 

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