2-22-2008 

1 

The Effects of E20 on Metals Used in Automotive 

Fuel System Components 

 Bruce Jones, Gary Mead, Paul Steevens, and 

Mike Timanus 

 Minnesota Center for Automotive 

Research at Minnesota State University, Mankato 

ABSTRACT 

The focus of this study was to compare the effects of 

E20 versus E10 and gasoline on metal materials found 

in automotive, marine, and small engine fuel system 

components. Metal samples were prepared using SAE 

and ASTM standards and exposed to blends of Fuel C; 

Fuel C and 10% aggressive ethanol; and Fuel C with 

20% aggressive ethanol at an elevated temperature of 

45 °C for 2016 hours. The fuel was changed in weekly 

intervals with photo images and mass loss/ gain data 

recorded at the 1st, 3rd, 6th, and 12th week. 

INTRODUCTION 

Minnesota Governor Tim Pawlenty signed a bill on May 

10, 2005 that requires by volume 20% of the fuel sold in 

Minnesota to be ethanol. Currently, gasoline sold in 

Minnesota contains 10% ethanol (E10) by volume. 

Ethanol, C2H5OH, is an alcohol that can be derived from 

starches such as corn or materials containing sugars 

such as sugar cane. Ethanol can also be made from 

cellulosic materials such as grasses by converting them 

into sugars. However, this process is much more cost 

intensive and has not yet reached commercial 

production levels. Ethanol is considered a renewable 

fuel and is also classified as an alternative fuel since it 

can be used as a substitute for gasoline. 

The passage of the law is only the first step. The fuel 

may not be used on public roadways until a federal 

section 211f waiver is obtained from the United States 

Environmental Protection Agency (EPA). Extensive 

testing in five areas: vehicle driveability, vehicle 

emission control system effectiveness and durability, 

vehicle tailpipe and evaporative emissions, fuel system 

material compatibility, and public health must be 

conducted in order to obtain the waiver (C. Jewitt, 

personal communication, July 6, 2005). This will be a 

costly and timely process requiring many different 

studies. 

This paper represents one in a series of four papers that 

focus on the effects of 20% ethanol-blended fuel (E20) 

on fuel system components. This paper provides some 

of the background information on E20 and the various 

laws that affect its use as an on-road fuel. Next, it 

contains a brief review of literature on E20 with a 

particular focus on material compatibility issues. Finally, 

it investigates the issues of designing the material 

compatibility study in terms of standards, procedures, 

and equipment needed to carry out the testing. 

MINNESOTA ETHANOL LEGISLATION 

On May 10, 2005, Minnesota Governor Tim Pawlenty 

signed into law a bill requiring ethanol to constitute 20% 

of the gasoline sold in the State of Minnesota. The bill 

allows for two methods of achieving this. First, if by 

December 31, 2010 the volume of ethanol sold in the 

State through the combination of E10 and E85 reaches 

20% of the total gasoline sold in the State, then the goal 

will be met and there will not be any changes in the fuel 

sold. If the combination of the two fuels’ ethanol content 

does not reach at least 20% of the total fuel sold, then 

by August 30, 2013 the ethanol content of gasoline will 

be increased from 10% to 20% by volume (Eisenthal, 

2005). 

The second method, 20% ethanol in all gasoline, 

requires the EPA to approve a waiver for the use of E20. 

EPA waivers may be granted one of two ways. The EPA 

can review the application and supporting data and grant 

the waiver. Or, if the EPA fails to provide a decision on 

the waiver within 180 days, the waiver is automatically 

granted. This clause is of particular concern because 

the original fuel waiver for E10 was granted because the 

EPA failed to make a decision in 180 days. The 

Minnesota law explicitly states that the failure of the EPA 

to act shall not be deemed an approval. 

LITERATURE REVIEW 

The passage of the Minnesota E20 legislation raised 

many questions about the effects of E20 on non-flex fuel 

vehicles. All vehicles sold in the United States since the 

early 1980s are compatible with E10, but whether or not 

they are compatible with E20 is not known. Before E20 

can be sold in Minnesota, a section 211f waiver needs to 

be obtained from the United States Environmental 

Protection Agency (EPA). In order to obtain a waiver, 

extensive research and testing will need to be conducted 

in five areas: driveability, fuel system material 

compatibility, tailpipe and evaporative emissions, 

emission control system effectiveness and durability, 

and health effects. This research and testing will be 

conducted to ensure that the fuel does not cause any 

more problems than gasoline in the five categories. 
 2-22-2008 

2 

The fuel systems on vehicles produced today are seeing 

an ever-increasing amount of ethanol-blended fuels and 

are expected to have a usable lifespan of 15 to 20 years. 

Currently, all fuel systems are compatible with E10, but 

as increased ethanol blends become more prevalent, 

the need to quantify the effects of higher blends on 

materials is necessary. Unfortunately, there is little 

information on the non-linear effects of increased 

ethanol blends on fuel system materials. This means 

that as the concentration of ethanol increases from 0 to 

100% there is no model that accurately predicts the 

effects on materials. In fact, neat ethanol and neat 

gasoline often have a smaller negative impact on 

materials than gasoline-ethanol blends. To compound 

this problem, mid-range blends of 15 to 50%, often have 

the largest negative impact on materials. 

The MSU material compatibility study started out like 

most research with a comprehensive review of the 

literature. To guide this review, a few questions were 

asked: (a) What literature exists on E20 and materials? 

(b) What materials are in a fuel system? (c) What 

standard test procedures are used to validate a material 

for compatibility with a fuel? (d) By what criteria is a 

material deemed compatible or incompatible with a fuel? 

With these questions in mind, a thorough review of the 

Society of Automotive Engineers’ (SAE) technical paper 

library was conducted along with an extensive internet 

search. Also, Original Equipment Manufacturers 

(OEMs), Tier I and II suppliers (supply parts to the 

OEMs), and material testing laboratories were contacted 

for information. 

During the search for information on E20, it became 

apparent that there was very little information publicly 

available. Most OEMs have tested with a fuel close to 

E20, such as E25 because of its extensive use in Brazil, 

but retain this information as proprietary. Several small 

material studies mentioned E20 or tested a blend close 

to E20 such as E25, but these studies offered only a 

small portion of the information that would be necessary 

for a waiver. In fact, only one major study on E20 was 

found, the Orbital Engine Company’s study for the 

Commonwealth Government of Australia conducted 

from October 2002 through March 2003 (Orbital, March 

2003, May 2003). 

The Orbital study was extremely comprehensive, 

covering both automobiles and small engines in areas of 

emissions, driveability, material compatibility, durability, 

and a well-to-wheel study. With regards to material 

compatibility, the Orbital study tested actual components 

from vehicles. The study found that E20 caused 

significant problems with many metal, plastic, and rubber 

components that gasoline did not. The Orbital study was 

carefully reviewed at MSU. The study identified 

significantly higher levels of discoloration and tarnishing 

on components exposed to the E20 than the gasoline 

reference fuels in the study. However, it should be 

noted that E10 was not included in this study and other 

research studies have noted similar discoloration and 

tarnishing associated with the use of E10. Also, it is 

believed that corrosive water was added to the E20 

blends at levels high enough to cause phase separation 

but was not added to the gasoline reference fuels. 

According to SAE recommended practice J1681 

Gasoline, alcohol and diesel fuel surrogates for 

materials testing, corrosive water is only added to 

gasoline or ASTM Fuel C, not ethanol (SAE, 2000). This 

test method could be a reason for the extreme negative 

results that the Orbital study reported. 

FORMULATING THE EXPERIMENTS 

With a lack of available literature on ethanol 

compatibility, it became apparent that actual material 

compatibility experiments would be necessary to answer 

some of the questions about the effects of E20. It was 

also determined that E10 should be included in any 

material compatibility tests as a reference to the 

changes caused by ethanol. Ethanol does cause 

different changes to materials than gasoline. But, if E20 

does not cause a larger negative impact on materials 

than E10, an accepted motor fuel, then E20 would be 

acceptable. The inclusion of E10 in the testing for the 

purpose of differentiating acceptable changes caused by 

ethanol is a significant component of the MSU material 

studies. 

PROCESS OVERVIEW 

Four standard practices from Society of Automotive 

Engineers (SAE) and the American Society for Testing 

and Materials (ASTM) were used to develop the specific 

testing procedures. The procedure developed was a 

combination of SAE J1747, Recommended methods for 

conducting corrosion tests in gasoline/methanol fuel 

mixtures, and ASTM G31, Standard practice for 

laboratory immersion corrosion testing of metals. The 

test fuels were blended as per SAE J1681, Gasoline 

alcohol and diesel fuel surrogates for materials testing. 

SAE J1747 modifies ASTM G31 to make it fuel-testing 

specific. A decision was made to use the exposure 

method of ASTM G31 over SAE J1747 because it 

allowed more data to be collected. Originally, SAE 

J1747 called out for all of the samples to be completely 

immersed. Due to the fact that corrosion can occur at 

the liquid/vapor level and in the vapor level itself, a 

decision was made to use ASTM G31’s suggested 

exposure where as one sample is completely immersed, 

the second sample is halfway immersed, and the third 

sample is exposed to vapors only. This allowed data to 

be collected from all three types of exposures as the 

material would be in use. 
 2-22-2008 

3 

All testing and data collection took place in a room 

equipped with a ventilation system designed to handle 

hazardous fumes. All samples were prepared as 

specified by ASTM G1, Standard practice for preparing, 

cleaning, and evaluating corrosion test specimens. After 

the samples were prepared, the weights and dimensions 

were measured to provide a baseline for comparison. 

Photographs of the color and surface texture were also 

taken. 

Three bottles were used for each material. Each 

contained three coupons of a specific material and one 

of the three test fuels. Next, 510 ml of the appropriate 

test solution was added to each of the bottles along with 

the three test samples on the sample stands. The 

bottles were placed in the oven unsealed until a 

temperature of 45 ± 2 °C was reached. Upon 

temperature stabilization, the bottles were sealed. The 

samples were exposed to the test fluid for a period of 

2016 hours. Each week, the test solution was changed 

to minimize bulk solution composition changes, oxygen 

depletion, and to replenish ionic contaminates. Finally, 

the samples were photographed and weighed after the 

1st, 3rd, 6th, and 12th week. Refer to Appendix A for a 

detailed step-by-step procedure. 

MATERIALS 

Based on the review of numerous material compatibility 

studies, only the raw materials used in the construction 

of fuel system components were tested, rather than 

actual components. Testing raw materials allows for 

much broader coverage than testing components. For 

instance, the results from a test on mild steel could 

cover fuel lines, fuel rails, tanks, and injectors of any 

manufacturer using that material. This was determined 

to be more practical than testing each of the 

components individually. Also, many industry-accepted 

standard tests require specimens of specific dimensions 

that would be difficult to obtain from actual components. 

The list of materials used in the fuel systems of 

automobiles from the 1970’s forward, marine engines, 

non-road engines, and fuel dispensing equipment is 

immense. It would be virtually impossible for one study 

to test every material and combination of materials used. 

The materials list for this study was created from various 

sources such as literature reviews, manuals, and 

recommendations from fuel system and engine 

manufacturers. After the list of metals was assembled, it 

was forwarded to a list of fuel system engineers from 

several OEMs and Tier I and II suppliers for peer review. 

Finally, materials that are commonly used in flex-fuel 

vehicle fuel systems were removed from the list because 

they have already been proven compatible with any 

blend of ethanol from 0 to 85%. The 19 materials 

included in the study are listed below. 

• brass 260 

• brass 360 

• cast iron 

• copper 110 

• 6061 aluminum 

• 3003 aluminum 

• cast aluminum mic 6 

• 60/40 tin/lead solder 

• 1018 steel 

• 1018 steel tin plated 

• 1018 steel nickel plated 

• 1018 steel zinc plated 

• 1018 steel zinc tri-chromate plated (hexavalent) 

• 1018 steel zinc di-chromate plated (hexavalent 

free) 

• 1018 steel zinc-nickel plated 

• terne plate 

• Zamak 5 

• magnesium AZ91D 

• lead 

After the testing had begun, magnesium AZ91D was 

identified by small engines manufacturers as an alloy 

used in many fuel systems. Because the addition of 

another sample was not possible due to size constraints 

of the oven, the Magnesium samples were tested at a 

later date with the materials from another study at a 

slightly higher temperature of 55 ± 2 °C. 

SAE J1747 suggests a sample size of 1 x 4 x 0.125 in. 

strips for testing because three will fit in the test bottle 

and maintain a minimum surface area to fuel volume 

ratio of 0.2 cm2

/ml. Due to the decision to test samples 

in three states, immersed, liquid/vapor, and vapor, this 

size would not allow sufficient space for the vapor 

sample. A new sample size of 1.5 x 1.5 x 0.125 in. was 

chosen instead. This allowed ample space in the test 

bottle for the vapor sample, while maintaining the 

minimum surface area to fuel volume ratio of 0.2 cm2

/ml. 

The raw materials for the samples were obtained in 

either 1.5 x 0.125 in. strips or 12 x 12 x 0.125 in. sheets. 

The test samples were cut from the strips or sheets 

using a horizontal band saw and then milled to the final 

dimension to ensure squareness and accuracy. After 

milling, a 9/32 in. hole was drilled to provide a means of 

suspending the sample. Next, an identification number 

was stamped on each sample to identify the material, 

the state in which it was to be tested, and the fuel it was 

to be tested in. All of the preparation work was done 

before sending out the samples that needed plating to 

ensure that the entire surface was covered. Finally, 

before testing, all samples were prepared in accordance 

with ASTM G1, Standard practice for preparing, 

cleaning, and evaluating corrosion test specimens. 
 2-22-2008 

4 

TEST FUEL 

The test fuel selection for this research was a major 

focus in the test plan development. In the review of the 

literature, several studies were identified in which it was 

difficult to determine the specific composition of the base 

gasoline or ethanol components. The test fuels used in 

this study were based on the test-fuel standard specified 

in SAE J1681, Gasoline alcohol and diesel fuel 

surrogates for materials testing. This paper was the 

result of a task force formed in the early 1990’s for 

testing materials with methanol. Since then, the 

standard has been altered to include many fuels. The 

task force adopted ASTM Fuel C to use as a reference 

for gasoline in material compatibility testing. ASTM Fuel 

C represents a worst-case-scenario gasoline due to its 

composition of 50% iso-octane and 50% toluene. The 

iso-octane represents the alkane group that makes up 

40 to 70% of gasoline (Harrigan, Banda, Bonazza, 

Graham, Slimp, 2000, p. 2). It is important that the 

alkane group is represented for two reasons. First, they 

make up a large percentage of gasoline and second, 

they can cause swelling in polymers (plastics and 

elastomers). The toluene represents the aromatic group 

that makes up 20 to 50% of gasoline (p.2). Aromatics 

can cause swelling in polymers, but they also help 

suspend alcohols within the fuel mixture. 

Synthetic ethanol, not fuel-grade ethanol, should be 

used for materials testing because its known 

composition “will help to minimize some of the variables 

in the use of ethanol as a fuel test component” (Harrigan 

et al., p. 5). Many impurities can be found in fuel-grade 

ethanol including sulfuric acid, acetic acid, water, and 

sodium chloride. “The acid is formed either in the 

alcohol production process or due to oxidation of the 

alcohol during handling, transfer or storage” (p. 3). 

Water also is a by-product of production and can cause 

metal corrosion, especially when combined with sodium 

chloride. It is important that these are represented in the 

test fuel because they can cause material compatibility 

issues. As per SAE J1681, these impurities were added 

to the synthetic ethanol to form aggressive ethanol. 

Aggressive ethanol is a worst-case-scenario fuel that 

would still be acceptable under ASTM D4806, Standard 

specification for denatured fuel ethanol for blending with 

gasoline for use as automotive spark-ignition engine fuel

(ASTM, 2006). 

All fuels used in this study met SAE Standard J1681’s 

criteria. The three test fuels used included 

Surrogate gasoline [C] - ASTM Fuel C, 50/50 

toluene iso-octane mixture (500 ml toluene and 

500 ml iso-octane) 

E10 fuel [C(E10)A] - 90% Fuel C + 10% 

aggressive ethanol (450 ml toluene, 450 ml isooctane, 100 ml aggressive ethanol) 

E20 fuel [C(E20)A] - 80% Fuel C + 20% 

aggressive ethanol (400 ml toluene, 400 ml isooctane, 200 ml aggressive ethanol) 

Aggressive ethanol consists of synthetic ethanol 816.00 

g, de-ionized water 8.103 g, sodium chloride 0.004 g, 

sulfuric acid 0.021 g, and glacial acetic acid 0.061 g 

(SAE J1681 Appendix E.1.2). 

APPARATUS 

The samples were placed in 1 L, high-density 

polyethylene (HDPE) bottles for the immersion testing. 

A wide mouth design was selected to allow easy access 

to the test samples. A test stand to support the three 

samples, one immersed, one halfway immersed, and 

one suspended above the liquid in the vapors, was 

designed and fabricated due to the lack of a suitable 

commercially available unit (see Figure 1). These 

stands were constructed from HDPE due to its insulating 

properties and resistance to chemical attack. The test 

stands resembled a ladder with three, 1⁄4 in. horizontal 

rungs running between two, 1⁄2 in. vertical rods. Samples 

were hung on the rungs by a 9/32 in. diameter hole and 

the entire assembly extended up to the neck of the bottle 

to facilitate easy removal, yet allowed the bottles to be 

sealed tightly. 
 2-22-2008 

5 

Figure 1. Samples on test stand and bottle 

An explosion-proof friction air oven was used to maintain 

the samples at 45 ± 2 °C. It uses the heat generated by 

circulating air to maintain the temperature instead of an 

element or a flame. This is very important when heating 

combustible liquids in the presence of oxygen due to the 

potential for an explosion if the vapors were to come into 

contact with an ignition source. 

DATA COLLECTION 

The samples weights and dimensions were recorded 

before being exposed to the test fluids. Along with 

weight, a photo was taken of each sample to provide a 

reference of the original color and surface texture. The 

color of the solution was also noted before each weekly 

fuel change. Throughout the 2016 hours of the test, 

data was collected after the 1st, 3rd, 6th, and 12th week. 

After a sample was removed from the test fuel, it was 

dried and weighed to determine any mass gains or 

losses. Next, the samples were cleaned by scrubbing 

with a bleach-free scouring powder and a soft bristle 

brush. This was done to remove any corrosion that 

occurred. After the corrosion was removed, the samples 

were weighed again to determine any mass losses. 

Three primary pieces of measuring equipment were 

used to collect the data. A micrometer with a resolution 

of 0.0001 of an inch was used to measure the 

dimensions of the test samples. A special micrometer 

with pointed anvils was used to measure corrosion pit 

depth and a Radwag WAX 220 analytical balance was 

used to measure the mass of the test samples. The 

balance has a linearity of ∀0.0002 g and a repeatability 

of 0.00015 g as outlined in the user’s manual. Based on 

the resolution and linearity of the scale, a weight change 

in a specimen less than 0.0008 g could be due to scale 

error and should not be considered a measurable 

change. 

DATA ANALYSIS 

Two methods of determining the effects of the three 

blends of fuels were incorporated into this study. The 

first was visual examination of the samples for pitting, 

surface texture change, and discoloration. The test fuel 

was examined for color change and loose by-products 

each week. The second was the mass loss analysis as 

described in ASTM G1 Section 8. 

VISUAL EXAMINATION 

The first method of determining the effects of the 

different fuel blends was through a visual examination of 

each sample. When examining the samples visually, 

corrosion and its different states need to be defined. 

According to the 1989 ASM International Handbook of 

Corrosion Data, edited by Bruce D. Craig of 

Metallurgical Consultants Inc, uniform / general 

corrosion is defined as, “A form of attack that produced 

overall uniform wastage of the metal” (p.1). Pitting 

corrosion is defined as, “A high localized attack of the 

metal creating pits of varying depth, width, and number. 

Pitting may often lead to complete perforation of the 

metal with little or no general corrosion on the surface” 

(p.1). 

The pictures of the samples before, during, and after 

were used to determine any discoloration, change in 

surface texture, or pitting. Pitting deeper than 0.025 mm 

was measured using a micrometer with pointed anvils. 

For the purpose of this study, discoloration was 

considered acceptable because fuel system components 

are generally not aesthetic parts. Also, light pitting (less 

than 0.025 mm) that did not result in loose by-products 

was considered acceptable. However, deep pitting 

(greater than 0.025 mm) or perforation was considered 

unacceptable. And, “heavy corrosion resulting in the 

production of loose corrosion by-products” was 

considered unacceptable, because these could 

potentially become lodged in fuel pumps, filters, 

injectors, etc... causing a failure (anonymous OEM fuel 

and corrosion engineer, personal communication, 

February 10, 2006). 
 2-22-2008 

6 

MASS LOSS 

To understand the effects of the different fuel blends in 

relation to time, the mass loss can be changed to a 

corrosion rate. The corrosion rate is a prediction of the 

amount of the material in millimeters per year (mm/yr), 

that a component would lose after being exposed to the 

fuel. This can be used to project the amount of time a 

component made of a particular material will last before 

failure. 

The data gathered from the original dimensions and 

weights were used along with the data collected from 

weighing the samples throughout the test to calculate 

percent mass lost or gained. If uniform corrosion had 

occurred, the corrosion rate was calculated in 

millimeters per year. Only corrosion rates higher than 

0.0025 mm/yr are reported in this study. Corrosion rates 

less than this require much longer immersion periods to 

determine. ASTM G31 recommends the following 

formula: [Hours = 50 / (corrosion rate in mm/yr)] to 

determine the length of time needed to accurately 

predict extremely low corrosion rates (ASTM G31, 

8.11.4). Corrosion rates less than 0.0025 mm/yr 

represent an insignificant loss of material over a 20-year 

time span. If pitting had occurred, then the corrosion rate 

was not calculated due to the inconstant nature of 

pitting, which would result in an inaccurate corrosion rate 

(ASTM G1, 8.2). Instead, the pit depths were measured 

using a micrometer with pointed anvils and recorded. 

Using the corrosion rate per year, perforation potential 

was calculated to determine if a leak would likely 

develop during a normal service life of 20 years. A 

material is considered acceptable if the corrosion rate 

allows a component to provide at least 20 years of 

service. 

The mass-loss analysis involves calculating the 

corrosion rate from the data gathered on each sample. 

This data includes the time of exposure in hours, the 

surface area of each sample, the density of the material, 

and a constant to convert units. The corrosion rate 

formula as per ASTM G1 Section 8.1 is as follows. 

Corrosion Rate = (K x W) / (A x T x D)

K = a constant in ASTM G1 Section 8.1 (8.76 *104

) 

T = time of exposure in hours 

A = area in cm2

W = mass loss in grams 

D = density in g/cm3

An example of the corrosion rate calculation on a 

sample of magnesium AZ91D exposed to test Fuel 

C(E10)A at the liquid/vapor interface is shown below. The 

sample had a surface area of 28.326 cm2

 and weighed 

4.0476 g before the soak process and 4.0194 g at the 

end of 2016 hours. 

Corrosion Rate = (87600 x -0.0282 g) / (28.326 cm2

 x 

2016 Hours x 1.77 g/cm3

) 

Corrosion Rate = -0.0244 mm/year 

The measure of mm/yr was chosen so that the time to 

corrode through materials of varying thickness could be 

determined. For example, if a 2.00 mm (0.080 in.) thick 

carburetor bowl made of magnesium AZ91D was 

exposed to the liquid/vapor interface of E10, it would 

take (2.00 mm / 0.0244 mm/yr) or 81.9 years to corrode 

through. This is well in excess of the expected 20-year 

service life. 

RESULTS 

Visual appearance and mass change data was used to 

verify if a material was compatible with the fuels. Also, 

the data from the E20 samples were compared to that of 

the E10 and Fuel C samples because the latter two 

represent approved fuels. If E20 did not cause any 

more significant changes than E10 or Fuel C, and met 

the criteria stated in the data analysis section of this 

paper, then a material was deemed compatible. 

VISUAL CHANGE 

Many of the materials showed discoloration after being 

exposed to the ethanol-blended fuels. In general, the 

samples exposed to E20 exhibited a greater degree of 

discoloration than the samples exposed to E10. Also, in 

all cases the sample that was completely immersed 

showed a greater degree of discoloration than the 

sample exposed only to the vapor. This could easily be 

seen on the liquid/vapor interface samples with the 

bottom half that was immersed being darker than the top 

half that was exposed to the vapor (see Figure 2). 

However, it should be noted that discoloration does not 

necessarily indicate a potential fuel system reliability 

problem. Also, because fuel system components are 

not aesthetic parts of the vehicle, discoloration is not a 

reason to deem a material incompatible. 
 2-22-2008 

7 

Only one material, lead, showed discoloration after 

being exposed to Fuel C. Eleven materials, listed below, 

showed discoloration after being exposed to E10. 

• 1018 steel 

• copper 

• lead 

• 1018 nickel plated steel 

• 1018 zinc-tri-chromate plated steel 

• brass 260 

• terne plate 

• solder (60/40 tin/lead) 

• Zamak 5 

• cast iron 

• magnesium AZ91D 

Finally, fourteen materials showed discoloration after 

being exposed to E20. This included the same eleven 

materials that were discolored by E10 along with cast 

aluminum and brass 360. No discoloration of the test 

fuel was noted throughout the study. 

Only Zamak 5, an alloy used in some carburetors, 

showed pitting when it was exposed to E10 and E20, but 

not Fuel C. The pitting was apparent on the liquid and 

liquid/vapor samples but not the vapor samples. 

Although the pitting could be seen with the naked eye, it 

was not easily measurable with a micrometer. Finally, 

there was a noticeable amount of loose corrosion byproduct in the E10 and E20 Zamak 5 containers when 

the fuel was changed. This is unacceptable because the 

loose corrosion by-product could clog components in the 

fuel system. It should be noted that Zamak 5 is often 

plated to make it more corrosion resistant for fuel 

applications and the samples used in this study were not 

plated. 

Figure 2. Zamak 5 samples after week 12: Fuel C (left), 

E10 (center), E20 (right) 

MASS LOSS ANALYSIS 

Several materials displayed measurable mass losses, 

0.0008 g or greater, in one or all of the test fuels by the 

end of the study. Only two of these materials, 

magnesium AZ91D and Zamak 5, displayed a mass loss 

large enough to potentially calculate an accurate 

corrosion rate or discuss further. The mass losses on 

the other materials were so small that they did not 

represent a concern, nor could an accurate corrosion 

rate be established as mentioned in the data analysis 

section of this paper. Refer to Appendix B for mass-loss 

data and corrosion-rate data for the individual samples. 

Magnesium AZ91D is a die casting alloy that is 

commonly used in carburetors and diaphragm pumps. 

The magnesium AZ91D samples exhibited a mass loss 

in all three test fuels, with the largest loss occurring on 

the liquid/vapor sample immersed in Fuel C. This 

particular sample had a corrosion rate of -0.0248 

mm/year. The samples exposed to E10 (liquid/vapor) 

and E20 (vapor) had similar, but slightly lower, corrosion 

rates of -0.0244 and -0.0224 mm/year, respectively. 

Even though these samples had a large enough mass 

loss to calculate a corrosion rate, the rate was small 

enough that potential problems in a 20-year life cycle 

would be unlikely and therefore was deemed 

acceptable. 

Zamak 5, a material used in some early OEM 

carburetors and aftermarket carburetors, demonstrated 

significant mass loss, pitting, and loose corrosion byproducts after being exposed to E10 and E20 during the 

2016-hour study. The samples exposed to Fuel C did 

show a mass loss, but it was too small for an accurate 

corrosion rate to be calculated and therefore did not 

represent a potential problem. The Zamak 5 samples 

that were exposed to only vapor demonstrated little or 

no changes in all three fuels. However, the samples that 

were exposed to the liquid/vapor mix and liquid only 

showed significantly higher levels of corrosion as the 

ethanol concentration was increased. There was also 

pitting evident on the samples placed in the E10 and 

E20. The E20 samples also darkened to a greater 

extent than the E10 samples and had a greater mass 

loss. The mass losses of the samples exposed to E10 

were 0.0393 g and 0.0568 g for the liquid/vapor and 

liquid samples, respectively. The samples exposed to 

E20 showed mass losses of 0.1318 g and 0.3384 g for 

the liquid/vapor and liquid samples, respectively. As the 

ethanol concentration increased from 10 to 20 %, the 

mass losses increased 3.5 and 6 times for the 

liquid/vapor sample and liquid sample, respectively (see 

Figure 3). The corrosion rate in mm/yr was not 

calculated for the E10 and E20 samples, as per ASTM 

G1 protocol, due the fact that pitting was observed. 

Overall, Zamak 5 was found to be incompatible with both 

E10 and E20 due to pitting and loose corrosion byproduct that could potentially clog fuel system 

components. Zamak 5 also exhibited an unacceptable 

mass loss in E20. It should be noted that Zamak 5 is 
 2-22-2008 

8 

often plated to make it more corrosion resistant and the 

samples used in this study were not plated. 

Figure 3. Zamak 5 mass loss comparison 

CONCLUSIONS 

This study tested and compared the effects of E20 to 

that of E10 and Fuel C on 19 different metals used in 

automotive, marine, and small engine fuel systems and 

fuel dispensing equipment. Eighteen of the nineteen 

metals were found to be compatible. One metal, Zamak 

5, exhibited unacceptable levels of corrosion in both E10 

and E20. It was deemed unacceptable in both fuels 

because of pitting and the formation of loose corrosion 

by-products that could clog fuel system components. 

Zamak 5 also exhibited an excessive mass loss when 

exposed to E20. Again, it should be noted that the 

Zamak 5 samples used in this study were not plated, 

which could be the reason that the corrosion problems 

found in this study with E10 are not seen on automobiles 

currently being used with E10. 

Different degrees of discoloration were observed in 

many of the other materials. While many of the 

materials yielded higher discoloration as the ethanol 

concentration increased, they did not show signs of 

pitting, loose corrosion by-products in the test fluid, or 

have a mass loss that exceeded a rate that would cause 

a failure within a 20-year life cycle. 

ACKNOWLEDGEMENTS 

This study would not have been possible without the 

support and recommendations from a number of 

ZAMAK 5 individuals, organizations, and companies including 

2016-Hour Change in Mass

-0.3500

-0.3000

-0.2500

-0.2000

-0.1500

-0.1000

-0.0500

0.0000

 Vapor Mixed Liquid

Grams

Fuel C

E10

E20

Briggs & Stratton 

Delphi 

Ford Motor Company 

General Motors 

Intertek Automotive 

Jewitt and Associates 

Kohler 

Minnesota Corn Research and Promotion Council 

Minnesota Department of Agriculture 

Renewable Fuels Association 

S&S Cycle 

Technology Applications Group 

TI Automotive 

Toro 

Toyota 

Zen Fuel LLC / Michael Harrigan 

REFERENCES 

ASTM Recommended Practice, (2006). Standard 

specification for denatured fuel ethanol for blending with 

gasoline for use as automotive spark-ignition engine 

fuel. ASTM D4806. 

ASTM Recommended Practice, (2004). Standard 

specification for automotive spark-ignition engine fuel. 

ASTM D4814. 

ASTM Recommended Practice, (2003). Standard 

practice for preparing, cleaning, and evaluating 

corrosion test specimens. ASTM G1. 

ASTM Recommended Practice, (1972). Standard 

practice for laboratory immersion corrosion testing of 

metals. ASTM G31. 

Clean Air Act, 42 U.S.C. § 7547 (1977). 

Craig, B. (1989). Handbook of corrosion data. Metals 

Park, OH. ASM International. 

Eisenthal, J. (2005, May). E20 “Bill finally reaches Gov. 

Pawlenty’s desk”. Minnesota Ag Connection. Retrieved 

October 22, 2005, from 

http://www.minnesotaagconnection.com/storystate.cfm?Id=405&yr=2005

Environmental Protection Agency. (1995, August 22). 

Waiver Requests under section 211 (f) of the clean air 

act. Retrieved October 28, 2005, from 

http://www.epa.gov/docs/OMSWWW/regs/fuels/additive/

waiver.pdf
 2-22-2008 

9 

Environmental Protection Agency. (1991, January 24). 

Regulation of fuels and fuel additives; Definition of 

substantially similar. Retrieved October 28, 2005, from 

http://www.epa.gov/otaq/regs/fuels/additive/jan91.pdf

Orbital Engine Company. (2003, May). Market barriers 

to the uptake of biofuels study: A testing based 

assessment to determine impacts of a 10% and 20% 

ethanol gasoline fuel blend on non-automotive engines - 

2000hrs material compatibility testing. Report to 

Environment Australia. 

Orbital Engine Company. (2003, May). Market barriers 

to the uptake of biofuels study: A testing based 

assessment to determine impacts of a 20% ethanol 

gasoline fuel blend on the Australian passenger vehicle 

fleet - 2000hrs material compatibility testing. Report to 

Environment Australia. 

Orbital Engine Company. (2003, March). Market barriers 

to the uptake of biofuels study: A testing based 

assessment to determine impacts of a 20% ethanol 

gasoline fuel blend on the Australian passenger vehicle 

fleet. Report to Environment Australia. 

Oxygenated gasoline, Minnesota Stat. §§ 52-239.791 

(2004). 

Oxygenated gasoline, Minnesota Stat. §§ 52-239.791 

(2005). 

SAE Recommended Practice, (2000, January). 

Gasoline, alcohol and diesel fuel surrogates for 

materials testing. SAE J1681. 

SAE Recommended Practice, (1994, December). 

Recommended practices for conducting corrosion tests 

in gasoline/methanol fuel mixtures. SAE J1747. 

Society of Automotive Engineers. (2000). A rational 

approach to qualifying materials for use in fuel systems. 

Warrendale, PA: Harrigan, M., Banda, A., Bonazza, B., 

Graham, P., & Slimp, B. 

Sun Refining and Marketing Company. (1988, April). 

Waiver application for 15% MTBE (EPA Publication No. 

EN-88-02, III-A-1). Washington, DC: U.S. Environmental 

Protection Agency. 

United States Department of Energy: Energy Efficiency 

and Renewable Energy. (2005, September 9). 

“Minnesota passes E20 law”. Retrieved October 22, 

2005, from 

http://www.eere.energy.gov/afdc/progs/ddown.cgi?/WHA

TS_NEW/480/1/0

TERMINOLOGY 

E10 - Fuel consisting of 90% gasoline and 10% ethanol 

E20 - Fuel consisting of 80% gasoline and 20% ethanol 

ASTM Test Fuel C - Test Fuel C is composed of 50% 

toluene and 50% iso-octane. 

Aggressive ethanol - Synthetic ethanol 816.00 g, deionized water 8.103 g, sodium chloride 0.004 g, sulfuric 

acid 0.021 g, glacial acetic acid 0.061 g (SAE J1681 

appendix E.1.2)

C(E10)A - Fuel consisting of 90% ASTM test Fuel C and 

10% aggressive ethanol 

C(E20)A - Fuel consisting of 80% ASTM test Fuel C and 

20% aggressive ethanol 

CONTACT 

Department of Automotive Engineering Technology 

Minnesota State University, Mankato 

205 Trafton Science Center East 

Mankato, MN 56001 

Phone: 507-389-6383
 2-22-2008 

10 

APPENDIX A 

 MnCAR 

Minnesota Center for Automotive Research 

10-25-07 

FROM Bruce Jones, Gary Mead, & Paul Steevens 

 Minnesota Center for Automotive Research 

 Minnesota State University, Mankato 

 Trafton Science Center 205E 

 Mankato, MN 56001 

 (507) 389-6383 

 (507) 389-5002 (fax) 

RE E20 Material Compatibility Testing Procedure - Metals 

Introduction 

This document is intended to outline the material compatibility testing procedures used by the Minnesota Center for 

Automotive Research (MnCAR) for the purpose of measuring the material compatibility characteristics of metals 

commonly found in automotive fuel systems. 

Standards Used 

Proposed testing will follow the procedures outlined in SAE J1747, J1681, and ASTM G1, G31 for immersion testing of 

metals. 

SAE J1747 (Dec94): Recommended Methods for Conducting Corrosion Tests in Gasoline/Methanol Fuel 

Mixtures

SAE J1681 (Jan00): Gasoline, Alcohol, and Diesel Fuel Surrogates for Materials Testing

ASTM G1-03: Standard Practice for Preparing, Cleaning, and Evaluating Corrosion Test Specimens

ASTM G31-72 (Re-approved 2004): Standard Practice for Laboratory Immersion Corrosion Testing of Metals

Properties Examined 

 mass loss/gain 

 pitting 

 appearance change 
 2-22-2008 

11 

Metals to Test 

Nineteen metals, nine specimens of each (3 specimens x 3 fuels): 1.5 x 1.5 x 0.125 in. squares. 

brass 260 steel 1018 aluminum 6061 

brass 360 steel 1018 nickel plated aluminum 3003 

cast iron steel 1018 tin plated cast aluminum mic 6 

copper 110 steel 1018 zinc plated magnesium AZ91D 

lead steel 1018 zinc di-chromate hexavalent free plated 

solder 60/40 steel 1018 zinc tri-chromate hexavalent chrome plated 

terne plate steel 1018 zinc/nickel plated 

Zamak #5 

Test Fuels 

Three test fuels used consisting of 

C Surrogate gasoline- "base” ASTM Fuel C 50/50 toluene iso-octane mixture (500 ml toluene and 500 

ml iso-octane) 

C(E10)A E10 fuel- 90% Fuel C + 10% aggressive ethanol (450 ml toluene, 450 ml iso-octane, 100 ml 

aggressive ethanol) 

C(E20)A E20 fuel- 80% Fuel C + 20% aggressive ethanol (400 ml toluene, 400 ml iso-octane, 200 ml 

aggressive ethanol) 

 

Aggressive ethanol consists of synthetic ethanol 816.00 g, de-ionized water 8.103 g, sodium chloride 0.004 g, sulfuric 

acid 0.021 g, and glacial acetic acid 0.061 g (SAE J1681 appendix E.1.2). 

Required Material 

A. Containers for testing- HDPE (high density polyethylene) bottles with a 1L capacity. 

B. Oven capable of uniformly heating the HPDE bottles to 45 ± 2 °C for 2000 hours. 

C. HDPE stands to separate the specimens while in the bottles. 

D. Analytical scale with a resolution of 0.5 mg to weigh the test specimens. 

E. Micrometer with and accuracy ± 0.001in to measure specimens. 

Specimen Preparation 

1. Prepare the 1.5 x 1.5 x 0.125 in. specimens by stamping an ID number on each and drilling mounting holes where 

necessary. All preparation work on plated specimens must be done before plating so that no base material is exposed 

during testing (ASTM G31, 7.5, 7.6; SAE J1747, 4.1.4.1, 4.1.4.2). 

2. Clean each specimen by scrubbing with a bleach-free scouring powder (Bon Ami), followed by a water rinse, and 

finally a rinse in acetone. All handling of the specimen from this point out must be performed using gloves or forceps to 

avoid contamination (ASTM G31, 7.8). 

3. Record each specimen’s weight using an analytical balance accurate to at least ± 0.5 mg (ASTM G31, 7.9). 

4. Measure the dimensions of each specimen using a micrometer accurate to at least 0.001 in. Calculate the surface 

area subtracting any holes (ASTM G31, 7.9). 

5. Photograph the specimens to show original color and surface texture. 

Test Procedure

1. Fill the 1 L HDPE bottles with 510 mL of the appropriate test fluid (SAE J1747, 4.1.3.1, 4.1.4.2). 

NOTE: In order to ensure even heating and exposure, all specimens should be placed in, or removed from the 

test fluid at the same time. Also, all bottles should be placed in or removed from the oven at the same time. 

2. Place three specimens of the same material on the HDPE test stand. After all of the test stands are loaded, place all 

of them into their appropriate test bottles so that the bottom specimen is completely immersed, the second specimen 

halfway immersed, and the third just exposed to vapors. Place the lid on the bottle, but do not tighten at this time to avoid 

pressure build up (ASTM G31, 8.10.3; SAE J1747, 4.1.4.2). 
 2-22-2008 

12 

3. Preheat the oven to 45 °C and maintain this temperature within ± 2 °C. Place all of the bottles in the oven at the same 

time and allow the temperature of the specimens to stabilize at 45 ± 2 °C. Once stabilized, fully tighten the lids on the 

bottles. This procedure will ensure pressure buildup in the bottles is minimized (SAE J1747, 4.1.3.2, 4.1.3.3, 4.1.5.4). 

NOTE: During fuel change or measurement, always remove all of the bottles at the same time from the oven to 

avoid uneven exposure. Immediately remove all of the test stands/specimens from all of the bottles to allow them 

to cool and dry. 

4. Change the test fluid weekly to minimize bulk solution composition changes, oxygen depletion, and to replenish ionic 

contaminants. Note any changes in the test fluid color or loose corrosion by-products weekly (ASTM 31, 4.1.4; SAE 

J1747, 4.1.2.2). 

5. Continue heating the submerged metal specimens for 2000 hours, and take corrosion measurements after the 1st, 3rd, 

6th, and 12th week (SAE J1747, 4.1.5.5). 

Specimen Inspection and Cleaning Procedure

1. Perform inspection and measurement after the 1st, 3rd, 6th, and 12th week while replacing the test fluid (SAE J1747, 

4.1.5.5). 

2. Gloves or forceps must be used at all times when handling specimens to prevent contamination. 

NOTE: Always remove all of the bottles at the same time from the oven to avoid uneven exposure. Immediately 

remove all of the test stands/specimens from all of the bottles to allow them to cool and dry. 

3. Photograph the specimens after they are dried, and weigh them before cleaning to determine any mass gains (ASTM 

31, 9.1). 

4. Clean the specimens with a bristle brush and a bleach-free scouring powder. If heavily corroded areas can not be 

cleaned by brushing, air driven walnut shells are to be used (ASTM 31, 9.3.1). 

5. After cleaning, weigh the specimens to determine mass loss. The mass loss will be the principle method for 

determining the level of corrosion for each material (ASTM 31, 10.1). 

6. If any pitting is discovered, measure it using a micrometer with pointed anvils. Take a photograph of the sample to 

show the pitting. Do not establish a loss per year value, as pitting is rarely consistent (ASTM 31, 10.2.1). 

7. If it appears that internal attack has not been a factor in the corrosion, then calculate the mass loss, in millimeters per

year, with the following formula: (K * W) / (A * T * D), where K = an ASTM constant (used to convert to millimeters per 

year), W = mass loss in grams to the nearest 0.001 g to correct for any losses during cleaning, A = area in cm2

 to the 

nearest 0.010 cm2

, T = time in exposure in hours to the nearest 0.001 h, and D = density in g/cm3 (ASTM 31, 11.2). 

8. If testing is to continue, refer back to steps 1-5 of the Test Procedure section. 
13 

APPENDIX B MASS CHANGE AND CORROSION RATE 

Fuel C Fuel E10 Fuel Vapor Mixed Liquid Vapor Mixed Liquid Vapo

before 4.5660 4.2890 4.3270 before 4.5637 4.0476 4.2334 before 4.0after 4.5497 4.2589 4.3053 after 4.5402 4.0194 4.2108 after 3.9

Change in Mass (g) -0.0163 -0.0301 -0.0217 -0.0235 -0.0282 -0.0226 -0.0

Corrosion Rate (mm /year) -0.0138 -0.0248 -0.0179 -0.0202 -0.0244 -0.0191 -0.0

before 35.1726 35.1298 35.1278 before 35.1176 35.2521 35.1395 before 35.0after 35.1726 35.1297 35.1275 after 35.1179 35.2518 35.1403 after 35.0

Change in Mass (g) NM NM NM NM NM 0.0008 NM Corrosion Rate (mm /year) NC/M NC/M NC/M NC/M NC/M NS NC/M 

before 39.8973 40.2768 39.9907 before 40.0638 40.1193 40.1089 before 40.1after 39.8969 40.2768 39.9906 after 40.0645 40.1172 40.1029 after 40.1

Change in Mass (g) NM NM NM NM -0.0021 -0.0060 NM 

Corrosion Rate (mm /year) NC/M NC/M NC/M NC/M NS NS NC/M 

before 38.0175 37.8497 38.0058 before 38.0088 37.9634 37.9290 before 38.0after 38.0170 37.8487 38.0061 after 38.0076 37.9608 37.9244 after 38.0

Change in Mass (g) NM -0.0010 NM -0.0012 -0.0026 -0.0046 NM 

Corrosion Rate (mm /year) NC/M NS NC/M NS NS NS NC/M 

before 11.9894 12.0125 12.1421 before 12.0231 11.9805 12.0513 before 12.1after 11.9897 12.0130 12.1433 after 12.0231 11.9801 12.0515 after 12.1

Change in Mass (g) NM NM 0.0012 NM NM NM NM 

Corrosion Rate (mm /year) NC/M NC/M NS NC/M NC/M NC/M NC/M 

KeyHighlighted Cells Significant Change in Mass (> 0.0008 g)NM Not Measurable because mass change was outside accuracy/precision capability of scale NC/M Not Calculated because Mass change was outside accuracy/precision capability of scaleNC/P Not Calculated because Pitting was observ edNS Not Significant enough of a corrosion rate (< 0.0025 mm /yr)Magnesium AZ91D1018 SteelCopperBrass 360Aluminum 3003
14 

Fuel C Fuel E10 Fuel Vapor Mixed Liquid Vapor Mixed Liquid Vapo

before 12.5156 12.5067 12.5564 before 12.4225 12.4891 12.5206 before 12.5after 12.5147 12.5068 12.5563 after 12.4217 12.4885 12.5202 after 12.5

Change in Mass (g) -0.0009 NM NM -0.0008 NM NM NM 

Corrosion Rate (mm /year) NS NC/M NC/M NS NC/M NC/M NC/M 

before 51.7746 51.0825 51.6412 before 52.6858 52.6618 51.7176 before 51.0after 51.7684 51.0756 51.6332 after 52.6845 52.6544 51.7223 after 51.0

Change in Mass (g) -0.0062 -0.0069 -0.0080 -0.0013 -0.0074 0.0047 -0.0

Corrosion Rate (mm /year) NS NS NS NS NS NS NS 

before 35.8358 36.1278 35.7120 before 35.8500 36.0347 35.7876 before 35.6after 35.8354 36.1274 35.7130 after 35.8499 36.0342 35.7856 after 35.6

Change in Mass (g) NM NM 0.0010 NM NM -0.0020 NM Corrosion Rate (mm /year) NC/M NC/M 0.0001 NC/M NC/M NS NC/M 

before 35.5065 35.5188 35.3381 before 35.6685 35.8266 35.5859 before 35.9after 35.5049 35.5160 35.3361 after 35.6679 35.8250 35.5825 after 35.9

Change in Mass (g) -0.0016 -0.0028 -0.0020 NM -0.0016 -0.0034 NM Corrosion Rate (mm /year) NS NS NS NC/M NS NS NC/M 

before 35.2673 35.5167 35.0492 before 35.5073 35.2863 35.4092 before 35.3after 35.2670 35.5162 35.0496 after 35.5077 35.2851 35.4063 after 35.3

Change in Mass (g) NM NM NM NM -0.0012 -0.0029 NM 

Corrosion Rate (mm /year) NC/M NC/M NC/M NC/M NS NS NC/M 

KeyHighlighted Cells Significant Change in Mass (> 0.0008 g)NM Not Measurable because mass change was outside accuracy/precision capability of scale NC/M Not Calculated because Mass change was outside accuracy/precision capability of scaleNC/P Not Calculated because Pitting was observ edNS Not Significant enough of a corrosion rate (< 0.0025 mm /yr)Aluminum 60611018 Nickel Coated SteelLead1018 Zinc Di-Chromate (Hexavalent Free) Coated Steel1018 Zinc Tri-Chromate (Hexavalent 

Chrome) Coated Steel
15 

Fuel C Fuel E10 Fuel 

Vapor Mixed Liquid Vapor Mixed Liquid Vapo

before 35.8451 36.0073 36.0557 before 35.7778 35.8873 35.6474 before 35.4after 35.8451 36.0061 36.0542 after 35.7776 35.8864 35.6462 after 35.4

Change in Mass (g) NM -0.0012 -0.0015 NM -0.0009 -0.0012 NM Corrosion Rate (mm /year) NC/M NS NS NC/M NS NS NC/M 

before 35.9483 35.4653 35.9028 before 35.5163 36.0325 35.9464 before 35.7after 35.9473 35.4636 35.9012 after 35.5165 36.0306 35.9444 after 35.7

Change in Mass (g) -0.0010 -0.0017 -0.0016 NM -0.0019 -0.0020 NM Corrosion Rate (mm /year) NS NS NS NC/M NS NS NC/M 

before 35.8610 35.8227 36.1638 before 35.9817 35.9930 35.8024 before 36.2after 35.8598 35.8216 36.1621 after 35.9812 35.9922 35.8000 after 36.2

Change in Mass (g) -0.0012 -0.0011 -0.0017 NM -0.0008 -0.0024 NM Corrosion Rate (mm /year) NS NS NS NC/M NS NS NC/M 

before 38.7669 38.8832 38.8826 before 38.8417 38.8662 38.8704 before 38.81after 38.7658 38.8870 38.8820 after 38.8414 38.8635 38.8658 after 38.8

Change in Mass (g) -0.0011 0.0038 NM NM -0.0027 -0.0046 -0.0

Corrosion Rate (mm /year) NS NS NC/M NC/M NS NS NS 

before 17.0354 16.7382 17.1234 before 16.8331 16.7840 16.3970 before 16.7after 17.0320 16.7336 17.1201 after 16.8302 16.7778 16.3855 after 16.7

Change in Mass (g) -0.0034 -0.0046 -0.0033 -0.0029 -0.0062 -0.0115 -0.0Corrosion Rate (mm /year) NS NS NS NS NS NS NS KeyHighlighted Cells Significant Change in Mass (> 0.0008 g)NM Not Measurable because mass change was outside accuracy/precision capability of scale NC/M Not Calculated because Mass change was outside accuracy/precision capability of scaleNC/P Not Calculated because Pitting was observ edNS Not Significant enough of a corrosion rate (< 0.0025 mm /yr)* For Brass 260, the "before" weight measurem ent was lost. The week 1 data has been substituted for the before measurement.Terne PlateBrass 2601018 Zinc Coated Steel1018 Tin Coated Steel1018 Zinc/Nickel Coated Steel
16 

Fuel C Fuel E10 Fuel 

Vapor Mixed Liquid Vapor Mixed Liquid Vapo

before 37.9335 38.5033 37.2485 before 38.9853 37.7488 39.8251 before 33.7after 37.9305 38.4997 37.2430 after 38.9837 37.7422 39.8182 after 33.7

Change in Mass (g) -0.0030 -0.0036 -0.0055 -0.0016 -0.0066 -0.0069 -0.0

Corrosion Rate (mm /year) NS NS NS NS NS NS NS 

before 32.0851 33.3180 29.1921 before 31.4755 27.6252 30.9663 before 32.2after 32.0842 33.3148 29.1913 after 31.4748 27.5859 30.9095 after 32.2

Change in Mass (g) -0.0009 -0.0032 -0.0008 NM -0.0393 -0.0568 NM Corrosion Rate (mm /year) NC/M NC/M NC/M NC/M NC/P NC/P NC/M 

before 12.2150 12.5064 11.2828 before 11.6278 11.8106 12.4761 before 12.2after 12.2133 12.5059 11.2823 after 11.6279 11.8113 12.4758 after 12.2

Change in Mass (g) -0.0017 NM NM NM NM NM NM 

Corrosion Rate (mm /year) NS NC/M NC/M NC/M NC/M NC/M NC/M 

before 33.6240 30.4415 32.7912 before 32.5202 30.5405 33.4194 before 34.3after 33.6238 30.4439 32.7944 after 32.5227 30.5450 33.4234 after 34.3

Change in Mass (g) NM 0.0024 0.0032 0.0025 0.0045 0.0040 0.0

Corrosion Rate (mm /year) NC/M NS NS NS NS NS NS Key

Highlighted Cells Significant Change in Mass (> 0.0008 g)NM Not Measurable because mass change was outside accuracy/precision capability of scale NC/M Not Calculated because Mass change was outside accuracy/precision capability of scaleNC/P Not Calculated because Pitting was observ edNS Not Significant enough of a corrosion rate (< 0.0025 mm /yr)Cast AluminumCast IronSolder 60Tin/40LeadZamak 5