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© 2015 HORIBA, Ltd. All rights reserved.

About Analyzing Abrasives

Jeffrey Bodycomb, Ph.D.

HORIBA Scientific

www.horiba.com/us/particle


Mechanics of abrasion

Abrasion is the interaction of a rock (the abrasive

particle) and a hard place (the work piece). Either

the abrasive gives or the work piece gives. Ideally

it is the latter.


Factors affecting abrasion

Contact force: more force causes faster abrasion

Loading: worn abrasive and cast off work material fills spaces between grains, reducing cutting efficiency while increasing friction

Use of lubricant/coolant/metal working fluid: can carry away swarf (preventing loading), transport heat (in some cases), decrease friction (with the substrate or matrix), suspend worn work material and abrasives to allow a finer finish.


Factors affecting abrasion

Difference in hardness between substances: harder abrasives cut faster and deeper.

Grain size (grit size): larger grains cut faster and deeper (and leave deeper scratches).

Grain shape: sharp corners help

Adhesion between grains, between grains and backing, and between grains and matrix determines how quickly grains are lost and how soon fresh grains (if present) are exposed.


Mohs scale

The Mohs scale is a qualitative scale built on knowing which material scratches which others. Since abrasives work by scratching, it is a handy way to think about materials.

Mohs Hardness

Material

1 talc

3 Calcium carbonate

5 enamel

7 quartz

8 emery

9 Aluminum oxide

10 diamond


Macro vs. Micro grits

Macro grits: Greater than 60 mm

Size is generally determined by sieves

Micro grits: Less than 60 mm

Traditional test by sedimentometer.

2 mm macro grit

40 mm micro grit


Table of sizes

Extracted from ANSI B74.12. See the full document for further details. This is Table 3.

Grit 100% min sieve

25% max sieve

35% min sieve

70% min sieve

5% max through sieve

16 8 14 16 16+18 25

All material through #8 sieve

No more than 25% on #14

At least 35% on #16

At least 70% on #16 and #18 combined

No more than 5% through a #25 sieve


Effect of Particle Size: Price


Size: Particle Diameter (mm) 0.01 0.1 1 10 100 1000

Colloidal

Suspensions and Slurries

DLS – SZ-100

Electron Microscope

Powders

Fine Coarse

Optical Microscopy PSA300, Camsizer

Laser Diffraction – LA-950

Acoustic Spectroscopy

Electrozone Sensing

Disc-Centrifuge

Light Obscuration

0.001

Macromolecules

Nano-Metric

Meth

od

s

Ap

ps

S

izes

Sedimentation

Sieves


Weigh % sample caught on known screen sizes

Solid particles 30 mm – 30 mm (and larger)

Advantages:

Low equipment

cost

Direct

measurement

method

No practical upper

limit

Disadvantages:

Limited lower

range

Time

Consuming

High Labor Cost

Need Large

Sample Available through www.retsch.com

Sieves


More information available through www.retsch.com

Replace Sieves

Tend to wear over time. It is difficult to tell when sieve results are “drifting” due to wear

Results depend on nature of shaking and loading leading to operator to operator variations in results.

Small number of size classes

Sieves

http://www.retsch.com/uploads/sl/10660f9418429a568b9678a167782ea6.jpg


Digital Image Analysis


Take a picture,

analyze for size

Measurement Results

Image Analysis


Static Image Analysis

Particles are dispersed (isolated) on a surface

Picture are taken from stationary particles

Camera or surface with particles is shifted, multiple images are taken from different positions, images are processed and evaluated

High resolution images is possible

Number of images/particles is limited (because of time limitations)

Preferred orientation of the particles on the surface (largest 2D)

HORIBA PSA300


Dynamic Image Analysis

Particles flow through the measurement volume of the instrument and the field of view of the camera

Particles are captured during movement, no other moving parts necessary

Capturing of many particle images in a short time interval

Limitations because of image rate of the camera(s)

Image quality is (a bit) worse

Particles are projected in random orientation (3D)

CAMSIZER


Data Evaluation

Binarize

Find Edges

Analyze Each Particle

Output Distribution

Raw Image


xc min

xc min

“width”

A

A‘ = A xare

a

“diameter over

projection surface”

xarea

“length”

xFe max

xFe max

Width is best suited for

comparison with sieves !

Shape parameters can be calculated!

Many Size Measures


x [mm]0.1 10

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Q3

Tinovetin-B-CA584A_BZ_xc_min_002.rdf

Syngenta-1mm-2min-Sieb.ref

Meßwertdiagramm:

D:\...-Demo-Muenchwillen\CAMSIZER-Messungen\Tinovetin-B-CA584A_BZ_xc_min_002.rdf

Meßaufgabe: Syngenta-BZ.afg

Digital Image Processing

Measuring of Width Sieving

Competing Measuring Methods

--- width measurement

-*- Sieving

comparison

CAMSIZER-measurement xc min (red) and sieving * (black)

xc min

xc min

“width”

18 © Retsch Technology GmbH


fitted result

CAMSIZER-measurement xarea (red) to sieving * (blue)

Fitting of CAMSIZER results to Sieving

19 © Retsch Technology GmbH


Shape Analysis

area of the

particle

perimeter of

the particle

circle with

same area

as particle

diameter of

circle of

same area


Shape Analysis

SPHT 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

0

10

20

30

40

50

60

70

80

90

Q3 [%]

Pharma-Product-1-30kPa-bonne-forme-_xc_min_009.rdf

Pharma-Product-1-30kPa_Vitesse-Adaption_xc_min_008.rdf

lactose-30kPa_xFemax_003.rdf

Pharma-Product-2-460_xc_min_008.rdf


Easy shape example

b/l0.4 0.5 0.6 0.7 0.8 0.90

10

20

30

40

50

60

70

80

90

Q3 [%]

A32L 2__xc_min_001.rdfA32L 2__xc_min_002.rdf

A32L 2__xc_min_003.rdfA32L 2__xc_min_004.rdfA32L 2__xc_min_005.rdf

Messwertdiagramm:C:\CAMSIZER4.4.9\CAMDAT\RT1707_Fraunhofer IZM\A32L 2__xc_min_001.rdfMessaufgabe: RT1707.afg

broken round

Length and shape numbers for single particles, from real

pictures

Precise analysis of the amount of broken particles by shape

detection


Fused Silica

2© Retsch

xc_min [mm]0.05 0.10 0.15 0.20 0.25 0.30 0.350

10

20

30

40

50

60

70

80

90

Q3 [%]

Minco50-100_BZ_fix35_10mmGS_convex_xc_min_009.rdf

RT1549_50-100_rec_sieve.ref

Graph of measurement results:

D:\...nuary\CAMDAT\Mesh-50-100\Minco50-100_BZ_fix35_10mmGS_convex_xc_min_009.rdf

Task file: RT1594_Minco30-50_convex_10mm-GS.afg

0.1 – 0.35mm

xc_min [mm]0.1 0.2 0.3 0.40

100

200

300

400

500

600

q3 [%/mm]Minco-50-100_Sample-4-05%_xc_min_001.rdf

Minco-50-100_Sample-3-05%_xc_min_006.rdf

Minco-50-100_Sample 1 Half Repeat_xc_min_005.rdf


C:\...-3-16\CAMDAT\Mesh-50-100-Sample-4\Minco-50-100_Sample-4-05%_xc_min_001.rdf

Task file: RT1594_Minco50-100_10mm-GS.afg


Different Aspect Ratio of Abrasives

b/l0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.90

10

20

30

40

50

60

70

80

90

Q3 [%]

SWSK-F24-Fraktion1_5Mess_xc_min002.rdf

SWSKL-HQ-F24-Fraktion1__xc_min001.rdf

ZWSK-F24-Fraktion1__xc_min001.rdf

ZWSK-F24-Fraktion1_5Mess_xc_min002.rdf

Meßwertdiagramm:

D:\...rklassen-Schleifmittel24\Fraktion 1\SWSK-F24-Fraktion1_5Mess_xc_min002.rdf

Meßaufgabe: Versuch Fraktion1.afg

Width/Length Aspect ratio

<= elongated/

non round

Cu

mu

late

d r

ela

tive

sa

mp

le v

olu

me

compact/ =>

round


Detection of Oversize Particles

2© Retsch

xc_min [µm]8 10 12 14 160

10

20

30

40

50

60

70

80

90

Q3 [%]

CA10 Feed 450kpa_xc_min_007.rdf

CA10 Feed 450kpa_xc_min_008.rdf

CA10 T18 C 450kpa_xc_min_004.rdf

CA10 T18 C 450kpa_xc_min_005.rdf

CA10 T18F-A 450kpa_xc_min_001.rdf

CA10 T18F-A 450kpa_xc_min_002.rdf

CA10 T18F-B 450kpa_xc_min_001.rdf

CA10 T18F-B 450kpa_xc_min_002.rdf


C:\...Camsizer4 3 19 XT\CAMDAT\RT1694 Microbeads\CA10 Feed 450kpa_xc_min_007.rdf

Task file: RT1694 PMMA 450.afg

Cum

ulat

ive

Dis

trib

utio

n

Particle size [µm]

4 Samples:

Red

Green

Blue

Violet xc_min [µm]13 14 15 16 17 18

99.0

99.2

99.4

99.6

99.8

100.0

Q3 [%]

CA10 Feed 450kpa_xc_min_av.rdf

CA10 T18F-B 450kpa_xc_min_av.rdf

CA10 T18 C 450kpa_xc_min_av.rdf

CA10 T18F-A 450kpa_xc_min_av.rdf

Graph of measurement results: Mean values, task RT1694 PMMA 450.afg

C:\...Camsizer4 3 19 XT\CAMDAT\RT1694 Microbeads\

CA10 Feed 450kpa_xc_min_008.rdf, CA10 Feed 450kpa_xc_min_007.rdf

Δ ~ approx 0.5% Vol.

Red with oversized particles

Green without oversize

Blue with oversized particles

Violet without oversize


width/

length =

aspect ratio

Sphericity

Symmetry

Convexity

xFe max

xc min

A P

r1

r2

S

A convex

A real

Particle Shape

maxFe

minc

x

x

P

A2

4

2

1

r

rmin1

2

1

convex

real

A

A


New (Old?) shape descriptors

CAMSIZER P4 Krumbeins Roundness and Sphericity

For proppants, sands, and other non-round, angular particles Compatible with ISO 13503-2 and API

Krumbein Sphericity SPHT_K measures the elongation of the particles (like w/l = b/l). Calculation based on W/L_perp = B/Lrec, with a different scaling

Average diameter of all corners divided by diameter of maximum inscribed circle

Krumbein Roundness RDNS_C measures the „angularity“, or „corner curvature radius“


Laser Diffraction


LA-960 Optics


Effect of Size

As diameter increases, intensity (per particle) increases

and location of first peak shifts to smaller angle.


Mixing Particles? Just Add

The result is the weighted sum of the scattering from each particle.

Note how the first peak from the 2 micron particle is suppressed since it

matches the valley in the 1 micron particle.


Why 2 Wavelengths?

30, 40, 50, 70 nm

latex standards

Data from very small particles.


Diamond

High refractive index: 2.41

0

50

10

20

30

40

0.010 50000.100 1.000 10.00 100.0 10000

100

20

40

60

80q

(%

)

Diameter (µm)

Un

ders

ize (

%)

Run D50 microns

1 30.80

2 30.44

3 30.49

4 30.53

Avg. 30.6

Std. Dev.

0.16


Silicon Carbide

High refractive index: 2.65

0

50

10

20

30

40

0.010 50000.100 1.000 10.00 100.0 10000

100

20

40

60

80

q (

%)

Diameter (µm)

Un

ders

ize (

%)

D50 microns

Dry 9.44

Wet 9.21


CMP Slurry (detect oversize)

Can detect added oversize particles!

Median Size : 1.65 µm

Colloidal Silica

Median Size : 0.031 µm

Median (Peak 1) : 0.031 µm Median (Peak 2) : 1.75 µm

Larger Silica

Mixture to check

sensitivity to

impurities


10 ml 35 ml 200 ml powders

•Wide range of sample cells depending on application

•High sensitivity keeps sample requirements at minimum

•Technology has advanced to remove trade-offs

Flexible Sample Handlers


How much sample (wet)?

Larger, broad distributions require larger sample volume

Lower volume samplers for precious materials or solvents

LA-950 Sample Handlers

Dispersing Volume (mL)

Aqua/SolvoFlow 180 - 330

MiniFlow 35 - 50

Fraction Cell 15

Small Volume Fraction Cell

10

Median (D50): 35 nm

Sample Amount: 132 mg

Median (D50): 114 µm

Sample Amount: 1.29 mg

Median (D50): 9.33 µm


Note: Fraction cell has only

magnetic stir bar, not for

large or heavy particles

Bio polymer Colloidal silica Magnesium stearate

It depends on sample, but here

are some examples.


How much sample (dry)?

Larger, broad distributions require larger sample quantity

Can measure less than 5 mg (over a number of particle sizes).

Median (D50): 35 nm

Sample Amount: 132 mg

Median (D50): 114 µm


Median (D50): 9.33 µm


Bio polymer Colloidal silica Magnesium stearate

It depends on sample …..

wet wet wet


Measurement Workflow

Measurement

Click “Measure” button

– Hardware measures scattered light distribution

– Software then calculates size distribution


Instrument to instrument variation

Sample CV D10 CV D50 CV D90

PS202 (3-30µm) 2% 1% 2%

PS213 (10-100µm) 2% 2% 2%

PS225 (50-350µm) 1% 1% 1%

PS235 (150-650µm) 1% 1% 2%

PS240 (500-2000µm) 3% 2% 2%

These are results from running polydisperse standards on 20 different instruments

20 instruments, 5 standards


Instrument to instrument variation

Industrial Samples

4 instruments, real sample


The Benefits

Wide size range Most advanced analyzer measures from 10 nano to 5 milli

Flexible sample handlers Powders, suspensions, emulsions, pastes, creams

Very fast Allows for high throughput, 100’s of samples/day

Easy to use Many instruments are highly automated with self-guided

software

Good design = Excellent precision Reduces unnecessary investigation/downtime

First principle measurement No calibration necessary

Massive global install base/history


Q&A

Ask a question at [email protected]

Keep reading the monthly HORIBA Particle e-mail newsletter!

Visit the Download Center to find the video and slides from this webinar.

www.horiba.com/us/particle

Jeff Bodycomb, Ph.D.

P: 866-562-4698

E: [email protected]

mailto:[email protected]

http://www.horiba.com/us/particlenews

http://www.horiba.com/us/en/scientific/products/particle-characterization/download-center/

about analyzing abrasives - horiba 1. 0 2. 0 3. 0 4. 0 5. 0 6. 0 7. 0 8. 0 9. 0 l/b 10 20 30 40 50...

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