[volt-nuts] PCBs with ceramic substrates

fala at gmx.net fala at gmx.net
Sun Apr 16 13:25:03 EDT 2017


Possibly Macor (machinable ceramic) from Corning, or the comparable 
Vitronit, which are both glass ceramics.

Comparable to borosilicate glass.
Extremely machinable (HSS or carbide tools, use proper speeds and 
coolant), continously stable until 800°C.
No safety concerns or toxic effects. The dust created when machining can 
be an irritant.

Available from Corning as standard size maxi slab of 36*36*6 cm.
Price = ?

Quoting Wikipedia for technical data for Macor:
---
Density: 2.52 g/cm³
Young's modulus [GPa @ 25°C]: 66.9  (FR4 = 21 - 24, Aluminium = 69, 
Steel = 200)
Specific stiffness [E6 m²/s²]: 26.55  (Al = 26, Steel = 25 +/- 0.5)
Poisson's Ratio []: 0.29 (FR4 = 0.118 - 0.136, Al = 0.32, Steel = 0.27-0.31)
Thermal conductivity [W/(m*K)]: 1.46  (FR4 ~ 0.3 - 1, Al ~ 300, Steel ~ 
15-50)
compressive strenght [MPa]: ~350
Electrical resistivity [Ohm*cm]: 1 E17 (FR4 = 1 E14, PTFE = 1 E23 to 1 E25)
Coefficient of thermal expansion [E-6 m/(m*K)]: 9.3 (FR4 ~ 13 , Copper = 
16.6)

Firat


Am 16.04.2017 um 13:08 schrieb John Devereux:
>
> Hi Chuck
>
> But the context is "PCBs with ceramic substrates". Are any of *those*
> tough? They may well be, perhaps you know of some? It does not help us
> with the subject much if there are ceramics with these amazing
> properties if they are not available as PCBs.
>
> There is also the question of exactly what properties of FR4 are
> limiting for "metrology" use.
>
> John



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