[time-nuts] OCXO housings - Why copper and not iron/steel?

[Richard (Rick) Karlquist]

Diamond, graphite and graphene are all forms of the
element carbon.  They all can have more conductivity
than silver.

Rick N6RK

On 10/30/2020 3:25 PM, Andy Talbot wrote:
> Actually, diamond has five times better thermal conductivity than silver,
> so is the most conductive element, although graphene is suspected to be
> better still.
> 
> 
> Andy
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> On Fri, 30 Oct 2020 at 22:17, Luiz Alberto Saba <las at intercat.com.br> wrote:
> 
>> My bad... copper is the second, losing only to silver, as a thermal
>> conductor.
>>
>> Enviado do meu iPhone
>>
>>> Em 30 de out. de 2020, à(s) 19:06, Luiz Alberto Saba <
>> las at intercat.com.br> escreveu:
>>>
>>> If my memory serves me, copper has the better conductivity of all the
>> periodic table...
>>>
>>> Enviado do meu iPhone
>>>
>>>> Em 30 de out. de 2020, à(s) 18:56, Attila Kinali <attila at kinali.ch>
>> escreveu:
>>>>
>>>> Moin,
>>>>
>>>> I have been looking at heat capacities of different materials
>>>> lately. One thing that struk me odd is, that the volumetric
>>>> heat capacity of copper, which is the thing that most people
>>>> use when building something that needs to have high heat capacity
>>>> to get stable temperature, has only a volumetric heat capacity
>>>> of 3.45 J/(cm^3·K). Meanwhile, the much cheaper iron has
>>>> a volumetric heat capacity of 3.53 J/(cm^3·K) and steel
>>>> even 3.75 J/(cm^3·K).
>>>>
>>>> In an OCXO, which is generally size limited, getting the most
>>>> heat capacity in the limited volume would be the main goal,
>>>> wouldn't it? Also optimizing for price would be a major thing.
>>>> I can understand that iron is probably not the right choice
>>>> due to its tendency to oxidize. But using a soft (annealed) steel
>>>> would be easy to machine, cheaper per piece and give almost 10%
>>>> higher heat capacity in the same volume.
>>>>
>>>> So why do people choose copper instead of steel?
>>>>
>>>>
>>>>            Attila Kinali
>>>>
>>>> PS: Fun fact: Water has a volumetric heat capacity of 4.18 J/(cm^3·K)
>>>> at 25°C. We should fill OCXOs with water! :-D
>>>>
>>>> --
>>>> <JaberWorky>    The bad part of Zurich is where the degenerates
>>>>                throw DARK chocolate at you.
>>>>
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