Hotplates or combined hotplate stirrers are used in most laboratories for basic heating and stirring applications.
Many models are offered with either a ceramic, ceramic coated or aluminium top plate. But what is the difference?
- Ceramic top hotplates have excellent chemical resistance, so are ideal if you are working with corrosive chemicals which may splash onto the plate surface.
- Heats up quickly.
- They can offer higher temperatures of up to around 450°C.
- They are easy to wipe clean.
- The white surface also means they are good for titrations or other work where clear visibility of colour is a must.
- Ceramic plates have a poor temperature uniformity over the plate surface and they also have cool edges. This is useful for operator safety but may not be suitable if you need heating all over the plate surface (e.g. the Stuart undergrad range have a 12x12cm heating area centred in the 15x15cm plate surface). If you are using a large vessel on the plate and need quite particular heating control, this will be very difficult to achieve because of the cool edges.
Warning! Ceramic hotplates must only be used to heat glassware, do not heat liquids in metal containers on a ceramic hotplate. They are also not suitable for sandbaths and any vessel which will reflect heat back onto the surface as this will cause cracking.
- Aluminium top hotplates are more robust and will withstand accidental knocks better than ceramic plates.
- They offer a consistent temperature all over the plate and become hot right up to the edges of the plate surface. Typically an aluminium plate will offer a temperature uniformity of ±10°C. This makes them more suitable for when fine temperature control is required – because the whole plate is heated, the temperature is easier to control.
- They have a greater temperature stability.
- They offer a lower maximum temperature than ceramic hotplates – up to <400°C.
- Metal top hotplates can also be used to heat metal vessels. If you are working with stainless steel beakers or other metal containers this is the best choice.
- Suitable for if you are wanting to heat multiple vessels at once due to the greater degree of temperature uniformity.
Warning! Aluminium plate surfaces are more susceptible to corrosive chemicals and can be difficult to clean.
Ceramic Coated Hotplates
- Ceramic coated hotplates are the best of both worlds. They combine the chemical resistance of a ceramic hotplate with the high levels of temperature uniformity achieved on aluminium plates.
- They have lower maximum temperatures than ceramic plates.
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One thought on “What is the difference between aluminium, ceramic & ceramic coated hotplates?”
I found it interesting how you mentioned how ceramic hotplates have excellent chemical resistance. My daughter has expressed interest in using ceramic sand to fabricate useful ceramics but has been hesitant to do so because she doesn’t know how her product can be implemented. I will be sure to pass this information on to her so she can assess all of her options!