British-made since 1976

Low scrap, guaranteed

Crucibles to 1,000 kg

Super zirconia crucibles for demanding vacuum melting

Magnesia stabilised zirconia with the low thermal expansion that lets one crucible survive pour after pour of superalloy — the reason aerospace casters specify it.

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Key benefits

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Vacuum stable to 1900°C

Holds its structure through repeated vacuum induction melts of nickel and cobalt superalloys.

Low thermal expansion

Minimal dimensional change over the heating cycle means the crucible is reused for many pours.

Clean, inclusion-free metal

A dense, non-reactive zirconia body keeps the melt clean for critical aerospace castings.

Magnesia stabilised

Magnesia stabilisation holds the zirconia phase stable, resisting spalling through severe thermal cycles.

Magnesia stabilised zirconia

A magnesia stabilised zirconia body engineered for the most demanding vacuum induction melting, with the low thermal expansion and phase stability that extend crucible life pour after pour.

Composition: Magnesia stabilised zirconia
Max service temperature: 1900°C
Capacity range: 8 to 265 kg

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Applications and alloys

The specialist choice for high end vacuum melting, proven with the nickel and cobalt superalloys used in aerospace investment casting.

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Furnaces: Vacuum induction melting
Alloys: Nickel and cobalt superalloys
Above 1900°C: See the lime stabilised range, to 2200°C

Technical data

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Isopressed round bottomed crucibles

Drg No	ID	OD	IL	OL	Full capacity, kg of steel
624	97	119	270	290	12.6
613	102	128	254	272	13.1
621	102	128	305	325	15.8
620	108	127	199	210	11.5
655	110	125	210	230	12.6
629	116	137	275	305	18.5
601	118	137	265	290	18.3
605	120	144	229	250	16.4
612	120	138	250	275	18
673	120	140	305	318	22
643	120	140	305	330	21.8
656	120	137	365	390	26.2
889	125	150	230	255	18
632	125	150	250	270	19.5
644	125	150	305	330	23.7
636	125	150	350	370	27.2
833	131	148	315	335	26.9
614	140	165	305	330	30
610	140	165	355	375	35
842	143	173	274	291	28
829	143	173	455	500	46
861	150	170	380	400	42
885	150	170	420	440	47
858	152	175	305	330	35
813	158	190	380	410	47
825	200	230	470	500	100
802	228	260	430	470	111
801	245	278	440	465	132

All dimensions in mm. Drg No: drawing number. ID: inside diameter. OD: outside diameter. IL: inside length. OL: overall length.

Isopressed flat bottomed crucibles

Drg No	ID	OD	IL	OL	Full capacity, kg of steel
677	95	116	190	220	8.7
603	95	120	181	221	8.1
604	95	120	241	275	10.8
684	95	115	305	330	13.7
875	95	115	356	370	16
843	102	128	319	332	16
688	106	125	205	220	14.3
873	110	135	205	230	15
855	118	141	233	252	16
840	127	148	175	200	14
839	127	148	249	274	20
660	127	150	247	268	19.8
678	127	153	356	380	28.7
639	130	150	268	285	22.5
659	136	165	290	315	26.9
611	140	165	290	315	28.3
851	140	165	317	341	30
641	140	165	380	405	37
828	143	175	300	325	31
859	152	178	304	330	35
883	158	190	300	330	37
821	170	203	395	425	60
882	175	203	300	330	43
848	178	212	410	435	65
837	178	212	470	500	74
827	206	242	456	483	96
811	245	278	465	500	140
831	258	305	431	458	140
835	280	320	435	465	170
895	300	340	590	650	265

All dimensions in mm. Drg No: drawing number. ID: inside diameter. OD: outside diameter. IL: inside length. OL: overall length.

Chemical analysis

Component	% by weight
SiO2	2.20
TiO2	0.14
Fe2O3	0.15
Al2O3	1.52
CaO	0.20
MgO	3.60
ZrO2 + HfO2	92.13

Typical chemical analysis, percentage by weight.

Physical properties

Property	Value
Apparent Porosity	17.84%
Bulk Density	4.35 g/cm³

The measurable difference

Every crucible we make is individually inspected before it leaves the works — the same standard we have held for fifty years.

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100%

Individually inspected

50 years

Manufacturing refractories in Britain

1,000 kg

Largest crucible capacity

Recommended backing mix

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Zirconia Backing Mix

Zirconia backing mix shares the crucible's coefficient of thermal expansion, so crucible and packing expand and contract together for a longer working life in vacuum furnaces.

Specification Stabilised zirconia

Other crucibles

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Alumina Crucibles

The workhorse of the range. High purity alumina handles both air and vacuum induction melting, with the thermal shock resistance and smooth, non-wetting surface the investment caster relies on.

Lime Stabilised Zirconia Crucibles

Trusted with platinum group metals at up to 2200°C. Lime stabilisation prevents volume changes, so the body resists spalling and erosion through the severest heating cycles.

Chrome Alumina Crucibles

A small addition of chrome oxide gives the alumina body its resistance to slag attack, extending crucible life in the air melting commercial foundry.

Magnesia Crucibles

Lighter than zirconia and preferred by some customers for X-ray analysis. The magnesia body carries lower running costs than stabilised zirconia.

Frequently asked questions

Magna supplies crucibles against drawing numbers or to new dimensions. Send your alloy, furnace type and melt size with an enquiry for a specification.

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What temperature can a super zirconia crucible withstand?

Super zirconia crucibles have a maximum service temperature of 1900°C, suited to high end vacuum induction melting. For platinum group metals, lime stabilised zirconia serves up to 2200°C.

Why choose zirconia over alumina for vacuum melting?

Which backing mix should be used with zirconia crucibles?

What sizes are super zirconia crucibles available in?

Specify the right zirconia crucible

Send the alloy, volume and process you're working with, and our technical team will confirm the drawing number or specify a new size.

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Drawings and specifications welcome
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