Keramicalia

Tel: +27 (0)11 412 3261 or +27 082 808 4757
We manufacture specialised refractories and ceramics.

Abrasion Resistant Materials

Abrasion resistant materials are difficult to select. "Abrasion" covers a wide range of conditions from impact by rocks to wear by fine particles in an air stream. All abrasion resistant materials have hard particles, the "aggregate", set in a strong "matrix". Usually the matrix wears down until it releases the aggregate particles. Consequently the surface acquires a rough texture. Some materials, such as Kerabrade C and Kerabrade 60 are designed to give a smooth, low friction surface

Kerabrade A is self leveling and self de-airing and requires no vibration. Developed for quick setting ultra thin perimeter walls. Used at ambient
temperature.

Kerabrade C is vibration castable, requiring intensive mixing.

Kerasic  is a self-levelling material based on silicon carbide.  Very Intricate shapes can be cast with it.

Kerabrade 60 is a putty-like plastic material, requiring intensive mixing. It is usually applied in a supporting structure of   hexmetal.

Kerapatch Stainless is a very hard material, applied in plastic form, for use between 400°C and 1700°C.

Kerapipe SiC is a silicon carbide plaster used with expanded metal.

Phospatch is a tough material used where chemical corrosion is also present.

Keralcast  Alumina based abrasion resistant castable.  Very easily mixed compared to most abrasion resistant materials.

Saffex An extremely hard and strong cementitious material. Suitable for floor tiles etc.

Stephenite  is a self flowing aluminosilicate material with very high strength at all temperatures from 400ºC to 1200ºC.

Urebrade  is an abrasion resistant material which can be applied very thin where weight is a problem.

Kerabrade D is a guniting abrasion resistant material developed for bends in large pipes.

Ninetysic is a silicon carbide material with etreme strength and hardness.

Kerabrade C

Description: An abrasion resistant high strength castable for use up to 1200°C. The matrix is very hard, and fracture will occur right through the aggregate grains.

Physical properties: Bulk density:  2,25g/cm³
Cold crushing strength:  100 to 150MPa
Permanent linear change: -0,2% after 800°C
Thermal conductivity: 1,6W/mK

Chemical analysis:

Al2O3 46.0%
FE2O3 0.9%
SiO2 49.0%

Installation: Place +7,5% water in a planetary (bakery type) mixer. Add half of the powder and mix until fluid. Add another quarter of the powder and mix until fluid. Slowly add the last quarter of powder, keeping the mix fluid. This will take about 5 minutes. The result is a self-levelling fluid.


Packing:
25kg plastic bags


Kerapatch Stainless

Description Kerapatch stainless is a phosphate

bonded chrome-alumina plastic material. Compared to conventional phosphate bonded chrome-aluminas, Kerpatch stainless has appreciably lower shrinkage, which results in superior structural integrity. It is supplied in soft plastic consistency, ready to use, in plastic buckets.

Applications:

1. Induction furnace repairs.
2. Metal splash shields.
3. Abrasion resistant linings.
4. Sliding gate maintenance.
5. Long-life ladles and teapot ladles.
6. Runners and launders.
7. Water-cooled plate protection.

Composition: The aggregate is fused chrome alumina: a high purity synthetic alpha alumina polycrystalline aggregate with good temperature and chemical stability. The matrix is tabular alumina which has good bonding properties and thermal shock resistance. The phosphate binder develops high strength at 100ºC. A complex series of dehydration reactions follow, culminating in a very strong anhydrous bond at 400ºC. The ceramic bond develops from 1000ºC, and rapidly above 1200ºC. Before the phosphate becomes pyroplastic, the chrome-alumina bond is well developed. Consequently it has very high strength over the whole temperature range from 100ºC to 1800ºC.

Metal Protection: A sheet of expanded metal, heavy duty, such as Mentex 72, is bent and tacked onto the steel substrate such that it is positioned 10 to 15mm above the surface. The material is then pressed into this continuous anchorage and hammered tight. The thickness is typically 25mm. This system is used in the following applications:

1. The outsides of steel shells or structures which sometimes come into contact with pouring steel or ferroalloys. Eg.: Launder casings, especially upper edges. AOD hoods. Ladles with hoods. Bases of steel structures especially where silicon spillage is possible. Spincaster cover ends.
2. Where occasional metal flow is expected yet there is insufficient space to apply conventional refractories: Eg.: Tundish overflows. Continuous caster emergency launders. Teapot ladle spouts. Handheld purging lances.
3. Abrasion resistant linings where geometry is too complex for tiles. eg.: nozzles. 4. Abrasion resistant linings where the temperature fluctuation destroys tiles, Eg.: burner quarls, coke discharge chutes.

Where mechanical stresses are great, another system is used; Hexmetal reinforcing. The sheet of honeycomb metal is welded onto stainless steel plate and the keraplas packed into it. Each cell of the honeycomb is independently anchored, and the structure can withstand severe expansion and contraction and mechanical abuse. This system can be used on water-cooled copper panels etc.

Chemical analysis

Al2 O3 82.0%
Cr O 7.2%
Fe2 O3 1.7%
SiO2 4.0%
TiO2 0.02%
CaO 1.5%
MgO 0.2%
Na2 O 0.3%
K2 O 1.0%
P2 O5 3.4%
Total 101.5%


Packaging; 25kg plastic buckets, ready to intstall.

See also: Keramor chrome alumina mortars Refractory paint, green. Keraplas; Similar material with green chromic oxide. Alumina castables; Keratab and Rubycast. Injectable Rubyject.

Kerabrade 60

Description; An abrasion resistant refractory installed in plastic form. used between 200ºC and 1000ºC. The matrix is hard and does not wear much faster than the aggregate.

Density; 2,5g.cm³

Cold Crushing Strength; 120 to 180 MPa (after 800ºC)

Thermal conductivity; 1.8W/mK

Permanent linear change after 800ºC; -0.35%

Maximum particle size; 5mm.

Chemical Analysis;

Al2 O3 54.0%
Fe2 O3 0.6%
SiO2 44.0%


Installation; Mix the powder in high shear mixer, preferably a bakery type planetary mixer for 1 minute. The add +5.3 to +5.8% water and mix for about 5 minutes. it will reach a plastic consistency suitable for hand packing. Normally it is placed into hexmetal reinforcing.

Packaging; 25kg plastic bags.

Kerasic

Description; Kerasic is alumina bonded silicon carbide. The main problem with silicon carbide is that it oxidises to silica. The alumina bond reacts with the silica to form a mineral called mullite, which has a needle like structure and imparts high strength, and has a melting point of 1850ºC. Kerasic is not as electrically conductive as other silicon carbide materials. Kerasic is a very fine grained material which can be poured like thick cream. Very detailed castings can be made with wall thicknesses down to 2mm. Plates have been made 300mm x 300mm x 5mm thick. The surface texture is very smooth, and the abrasion resistance of fired parts is excellent. The strength increases with repeated firing.

Cold crushing strength; 50 - 120 MPa

Chemical analysis;
Al2 O3      34.0%
SiO2           2.0%
SiC           58.0%
CaO           6.0%

Packaging; 25kg plastic bags.

Water addition for pouring; +12% vibration casting; +9%

Keracast 6

Keracast 6 is a totally cement free, CaO free material. It is consequently highly refractory. The chemical analysis is approximately as follows;

Al2 O

90

.0%

Fe2 O

0

.14%

SiO2

9

.0%

TiO2

0

.12%

CaO

0

.03%

MgO

0

.22%

K2 O

0

.04%

Na2 O

0

.2%

The mineral composition is about 87% alpha alumina, which is synthetic corundum, with a melting point of 2013ºC and 13% mullite, Al2O3 .SiO2 , with a melting point of 1850ºC. The material therefore contains very little liquid phase below 1850ºC. Both mullite and corundum are chemically inert and immune to attack by sulphurous or acid gases. To develop good strength we pre-fire the castings to 1200ºC, so that the silica is all present in the mineral mullite. Mullite grows in needle-like crystals, which enhance the strength of the composite. Corundum is the second hardest natural mineral, with a hardness of 9 on the Moh scale. (Diamond is the hardest, at 10 on the scale.) The only refractory materials with higher melting points are lime, magnesia and zirconia. All three are prone to thermal shock damage.

Mix with + 10% Super Binder L and vibration cast.

Packaging; 22,5kg powder and 2,5kg liquid Super Binder L.

Formulation no. 11484

Formulation no. 32031 is an upgrade with 94,5% Al 2O 3 and 4.4% SiO2.

Vibration cast with +11% Super binder L

Formulation no. 32035 is 93% Al₂O₃ and 6% SiO₂ Use +15% Super Binder L. Flows by tapping. % minutes working time.

Note that all of these are very high strength and difficult to break out.

Claimer; The above information had better be correct, since Dave Onderstall rests his reputation on it.

Phospatch

A patching material for hot surfaces and surfaces difficult to bond to.   Phospatch is virtually impervious.   It is totally silica free and immune to thermit reactions.   It is very sticky and sets in 10 minutes.

Chemical analysis;  Al2O3   88%

                                  CaO      4,5%

                                  P2O5     7%

Maximum service temperature;   1780°C

Density;   2,6g/cm3

Max. particle size;  3mm

Mechanical properties;    Phospatch has an exothermic setting reaction and expands slightly while setting.   It sets in 10 minutes, and grips onto nearly all surfaces, even copper.    Phospatch is not brittle; a hammer blow will make a slight dent rather than shatter it.    Test cubes on cold crushing strength deform without breaking.    The impervious structure gives immunity to chemical attack except on the surface.    Strength increases with temperature, but the malleability changes to a more brittle rigid ceramic structure.

APPLICATIONS;    Protection of waffle coolers from molten metal  contact.

                                Patching of launders, flues, any hot repairs of furnaces.

                                Patching of surface contact line in aluminium furnaces to prevent thermit reaction.

Colour;   Pure white.

Mixing;   Mix 100 weight parts powder to 22 weight parts liquid gives a gives a good workability, but can be used from pourable to rammable without any problem.  A lot of gas is evolved during mixing.  Do not make large batches, as the exothermic reaction is self accelerating.   Setting can be retarded by refrigerating the liquid binder.

Patches and castings can be heated up 20 minutes after  mixing.

Packaging;    5kg box repair kit, with mixing bowl and gloves.

                     10kg combined weight packs.

                     25kg packs, combined weight of powder and liquid.

                      25kg plastic bags of powder and 45kg polycans of liquid.

Shelf life;   3 years.

Development no. 39107

Claimer;   This information had better be correct, because Dave Onderstall stakes his reputation on it.

Kerabrade D

Kerabrade D is a bauxite based abrasion resistant material.  It is expensive and requires very intensive mixing in a planetary(bakery type) mixer.  It is a high silica fume vibration castable.  It is used mainly for precast shapes, since the dryout is difficult due to the very low porosity and permeability.

Maximum service temperature;  1200°C

Maximum particle size;  3mm

Bulk density after 110°C;  2,75g/cm³

Thermal conductivity at 800°C;  2,0W/mK

Cold Crushing Strength dried 110°C;  130MPa. (Rings like steel)

Chemical analysis;       Al₂O₃  78%

                                  Fe₂O₃  1,6%

                                  SiO₂  10%

                                  CaO  7%

                                  MgO  0,5%

                                  Na₂O  0,2%

                                  K₂O  0,1%

Mixing;  Add +6% to +7% water and mix for 12 minutes in a planetary mixer.  Initially the material will appear bone dry.  Puddling technique may be used.  Any deviation or short cuts will not achieve high strength.  Setting time is 2 to 6 hours.

Drying is very tricky, over 5 days for large castings.  Let us do it.

Packaging;  25kg polyethylene bags.

Shelf life;  Dodgy, better to use within 2 weeks.

Development no.  72303

Claimer;  This data had better be correct, since Dave Onderstall rests his reputation on it.

Archieplast

Probably the first ever abrasion resistant insulation material.   It is an aluminosilicate material containing hollow ceramic balls called cenospheres.  The matrix is extremely fine, cohesive and dense, but the bulk of the volume is sealed air bubbles.

The density is 1,7kg/l

The cold crushing strength climbs to around 50 MPa at 400deg C and drops back to 25 to 30 MPa at 1250deg  C

Installation;

Can be poured with an addition of +16% water, and will flow self-levelling.

Can be plastered with plus 12% water.

A variant is Archiecoat which can be plastered with +16% water and painted about 3mm thick with an addition of  +20% water.

Applications;

Protection of steel exposed to heat;  Ducting and shells of dust collectors etc.  Can be trowelled onto expanded metal.

Originator;

Archie Holder.

Development no.  94412

Packaging;

25kg plastic bags.

Shelf life ;

2 years.

Saffex

An extremely hard and strong cementitious material.   Suitable for floor tiles etc.

Chemistry;    70% silica,

                       20% Ciment fondu

                          0,11% P₂O5

The maximum particle size is 0.3mm, so fillers can be added.

Add +9,7% water and mix very intensively for about 7 minutes, until it flows.

The density is about 2,5.

The price is R8/kg + VAT

Further work is needed on deflocculation and setting speed.

Development no. 115201

Keralcast

Description:   Alumina based abrasion resistant castable.

This is new technology, previous high abrasion resistant ceramics are based on high additions of silica fume.   Keralcast has only 1% silica and can therefore be used at high temperatures, up to 1750ºC with virtually no molten phase present.

Density:     3.06 g/cm³

Max particle size:   5mm

Thermal conductivity:     2W/mK

Water addition:   Extremely low: +4.5%

Mixing: 7 minutes in a bakery mixer or 20 minutes in a pan mixer.

The consistency can be adjusted from putty to self-flowing, as preferred.

The setting time can be adjusted from half an hour to 6 hours, as preferred.

Testing:   Try to grind it on a bench grinder.

Shelf life:   2 years.

Packaging: 25 kg plastic bags.

Project no.   1142

Claimer:   This data sheet had better be correct because Dave Onderstall stakes his reputation on it.

Kerabrade A

A very high strength SCC (self compacting concrete). It differs from Dump Mixes in that it can be carried in buckets, but direct discharge into moulds or shuttering is preferred. Kerabrade A is self leveling and self de-airing and requires no vibration. It is derived from Perimeter 1 which was developed for quick setting ultra thin perimeter walls;  It develops 136 MPa in 4 days. Not for use at high temperatures. It is volume stable. Wear; It should wear to a smooth surface, because the matrix is as hard as the aggregate. (Most abrasion resistant materials become rough as the aggregate protrudes.) Kerabrade A is therefore ideal for ore chutes and sliding applications.

Maximum particle size is 7mm.

Density; 2,38

Mixing;   3 bags plus one polycan.

             78 weight parts powder to 22 weight parts liquid binder.

             100:28 or +28% liquid binder.

Flow time; 20 minutes.

Strip time; 3 hours

Packaging; 3 x 26kg bags plus 1x 22kg polycan of liquid binder for every 100kg.

Shelf life: 1 year.

Development No: 151568

Claimer; This provisional data sheet is incomplete. Kerabrade A is a new product and more data will be added as it becomes available.

Kerabrade S

An abrasion resistant material

Maximum service temperature;   1250°C

Composition;   Fused alumina, 80% Al₂O₃

Density;   2,6g/cm³

Cold crushing strength; air dry: 100 MPa      110°C: 120 MPa       1000°C: 150MPa. (+8%H₂O)

Applications:   Sliding or impact abrasion resistance, wet or dry. See detailed instructions below.

Mixing:   Add +8% water by puddling in a bakery mixer, 10kg batches, read instructions below.

Packaging: 10kg plastic bags

Development no. 85765

Kerabrade S is installed usually 15mm thick onto a steel shell to delay wear of the shell.   To optimize adhesion to the shell, the plaster is anchored to expanded metal. The preferred grade of expanded metal is Mentex 72. The expanded metal may be raised slightly off the shell. To do this the expanded metal is bent outwards at the desired intervals for welding. To bend it, cut a short (about 9mm) piece of pipe of diameter approximately   55mm.   Weld this to a rod about 800mm long. Place the expanded metal on a concrete slab.   Slide the pipe under the expanded metal to the point to be bent out. Strike the expanded metal sharply with a hammer until it reaches the concrete. This results in bumps raised about 5mm, which can now be welded to the shell.

Keragun D

Keragun D is a dense, wear resistant gunning material for use in areas exposed to extreme abrasion.

Good for high velocity ducting, bunkers, feed chutes and discharge chutes. The aggregate is highest purity bauxite, and the matrix contains tabular alumina.

Maximum service temperature; up to 1200°C

Maximum particle size; 3mm

Use an expert gunning operator to get optimal results.

Chemical analysis; Al₂O₃                               78%

                                  SiO₂ + CaO + MgO     17%

                                 Fe₂O₃ + Na₂O +K₂O      ‹4%

Rebound:                                                    ± 7%

Density:                               dried 110 ̊C :     2,7

Cold crushing strength:         dried 110 ̊C : 130 MPa

Packaging;                          25Kg thick polythene bags, 40 bags per pallet.

Development no. 164900

Claimer; This data had better be correct, since Dave Onderstall rests his reputation on it.

Ninetysic

A high thermal conductivity, highly abrasion resistant silicon carbide refractory.

Density:     wet: 2,5g/cm3.

Maximum particle size:   3mm

Maximum service temperature:   1600°c

Chemical analysis          SiC                     89%

Al2O3                      3%

SiO2                            6%

CaO                    1,5%

CSS:        110°C     50MPa

                1000°C  80MPa

Thermal Conductivity @ 1000°C ±16 W/mK

Casting:   Mix intensively with + 7% water and vibration cast.

Packing :    25kg transparent plastic bags

Shelf life:    3months

Development no:   23002

Claimer:   The above information had better be correct, as Dave Onderstall stakes his reputation on it.

Kerapipe SiC

A high strength abrasion resistant castable.

Applications:  Filling the ends of alumina tile lined pipes, and any parts where tiles are impractical to install.

Maximum service temperature:  1300°C.

Maximum particle size: 3mm

Density dry:        2.63g/cm³

Cold crushing strength: 110°C; 80 to 150MPa

Water addition: +6, 2%

Preparation: mix intensively in a pan mixer or bakery mixer for 7 to 10minutes.   For long working times, add 0, 2% boric acid to 85713 or buy 85776 with boric acid already added. With this retarder it can be kept in the mixer for half an hour without loss of strength.   Without retarder it sets in 10 minutes after mixing.

Composition: Silicon carbide.

High% of 70% alumina calcium aluminate cement.

High% extremely reactive alumina

High% top quality silica fume.

Packing : 10kg plastic bag

Shelf life 9 months

Development number: 85713 and 85776

Claimer: The above information had better be correct as Dave Onderstall stakes his reputation on it.

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